Chapter One: In the Sauna

Cortana laid on her back, eyes staring up at the ceiling as she felt John breathing on her neck, his forehead buried deep into the pillow, dull rhythmic thrusts shaking the bed around him.

Her head slipped off the bed, her neck bending at an uncomfortable angle against the headboard. She groaned in frustration.

"What is it?" John asked, stopping his thrusts and picking up his head to look at her.

"Nothing just, move off of me really quick," she said. She felt John slide his member out of her, the precipice of an orgasm lost in an instant as a cold wave of air washed over her pussy lips and caused her to shiver. Cortana scooted herself farther down on the bed, hurriedly arranging pillows underneath her head.

"Okay, I'm ready," she said, parting her legs to invite him in. John moved frustratingly slow as he moved back on top of her. Everything he did, even during sex, was done in an excruciating effort not to accidentally harm her. On some level Cortana found that sweet, but on another she found it exceedingly frustrating.

John laid himself back down on top of her, and then gently, far too gently, entered into her once more, resuming the missionary position with the same military formality as he did everything else.

Cortana closed her mind and attempted to concentrate, the dull, slow, monotonous thrusts eventually producing some effect. She felt a growing pressure in her lower abdomen, a steady rise of pressure whose ultimate peak was painfully out of reach. Still, she tried, letting all though leave her mind. She relaxed herself thoroughly, her body rising up in arousal until she was just almost…

John shuttered overtop of her, all his muscles tensing, eyes closing tight, and Cortana felt a spatter of warmth inside her, follow by a leaking drip on her inner thighs as John quickly withdrew, leaving Cortana's climax unachieved, all the while seeming to be blissfully ignorant of it. Cortana bit her lip in frustration, but said nothing.

John rolled off of her, again trying oh so very hard not to hurt her, and then laying on his side, gave her a quick kiss on the lips. It was rigid and awkward, but ultimately well intended.

That was, in large part, ultimately what their relationship had been for the past couple of months. John was the best friend Cortana ever had. Someone she cared about deeply and open herself up emotionally too. But when it came to any sort of intimacy it was always just that. Rigid and awkward.

As John laid down flat on his back on the opposite side of the bed, pulling the covers up over both of them, Cortana cleared her throat.

"So, what do you have planned for tomorrow?" she asked.

"Meeting with Palmer and Lasky in the morning about the Forerunner Installation Blue Team encountered the other day," he said. He almost seemed distracted, but Cortana let it slide, pulling the covers up and over her naked breasts.

Cortana glanced over at him with fake indignation. "You mean that Installation you helped blow up before my science team ever had a chance to check it out."

"It was necessary," John said in his defense.

"Sure it was," Cortana huffed. She elbowed him playfully in the ribs. "Better you than me going into that meeting. Lasky might be a big softy, but Palmer is going to rip you guys to shreds."

"Hmmm," was all John said. He dared not say anything else. The mere thought of being in a room for an extended period of time with Palmer made his heart beat slightly faster. There was something about the Commander. Something he forced himself never to dwell on for too long, but it was still significant enough for him to try to avoid her in most circumstances. The idea of having stand in close proximity to her for a number of hours did not excite him.

On the contrary, it thrilled him, and that was precisely the problem.

John quickly pushed the unwelcomed thoughts out of his mind. After all, he was a Spartan and she was his commanding officer. Purely professional relationship. No need to get flustered.

He looked over to see Cortana yawning, her pale slender arms disappearing underneath the covers as she curled up to go to sleep.

No reason to be flustered at all.

…

Cortana meandered down the long, bright, and grey hallways of the Infinity, her exercising t-shirt and short work out pants hugging her curvaceous and undeniably feminine figure tightly. If she had been walking down a normal street on Earth she would have undoubtedly elicited several whistles and head turns so swift and violent that they threatened to break necks. Perhaps even be hit on occasionally.

But this was a military vessel. A certain amount of decorum had to be observed.

But oh, there were still stares. Men, and even many women, stared at Cortana as she marched down the narrow hallways, their heads remaining motionless but their eyes following her for as long as humanly possible.

Cortana had to suppress a smirk. She would be lying if she said that she didn't get a thrill out of being so desirable to so many people. On the contrary, she deliberately sought it out, putting on workout clothes one or two sizes two tight, shorts a few inches too short. A direct breach of military regulation, but not one that anybody seemed willing to correct. Perhaps because all the officers were too busy staring at her ample breasts, a black exercise bra underneath pushing them up proudly.

She walked with an exaggerated gate, swinging her hips back and forth, giggling internally as a female Marine behind her slowed their step in an effort to try to look at her tight, swaying ass for as long as possible.

This was not a game she would ever tell John about. God forbid. He was a sweet boyfriend and a trusted confidant, but anything sexual caused him to be immediately uptight.

Cortana was far less uptight. Disastrously less. John was her first and only lover, and because of his inexplicable lack of passion with her in the bedroom, especially within the last two months ever since he had been placed directly under Palmer's command, Cortana had never endured an actual orgasm except under her own power.

Some deep darkness within her resented John for that. Cried out for Cortana to liberate herself, pleaded with her to gaze upon her vivacious curved body. The body of a goddess. A body that demanded to be taken roughly and passionately. Sometimes, often with her fingers flicking herself towards silent climax, this darkness completely consumed her thoughts. She felt guilty afterwards, and took to reminding herself at just how good of a mate John was in all other respects non sexual in nature.

Increasingly, though, it seemed as if that might not be enough.

Cortana reached her destination, sighing with relief as she saw that the small gym was empty.

Good. As much as she loved the male, and female, gaze, Cortana needed some time to collect her thoughts.

Cortana eyed each of the exercising equipment, tutting absentmindedly as she tried to make up her mind. Then her eyes fell on a machine that would fundamentally alter the entire course of her life forever.

A small sauna. Big enough for three or four people, the square box stood in the far corner of the gym. Fake wood sidings decorated the front, but perhaps the most interesting feature were the three square one way mirrors on the upper portion of the sauna. On the inside the mirrors functioned as windows, allowing a person to peer out into the rest of the gym, while all those outside the sauna only saw their own reflection if they tried to look in. It offered a sense of complete privacy while also preventing those inside from having to deal with a sense of enclosed claustrophobia.

It was perfect for what Cortana ultimately had in mind.

She strode over to the sauna, and upon entering immediately threw off her shirt, unfastened her bra, and threw both into the corner, the heat of the sauna washing over her as she closed the door behind her.

When the door slammed shut, a gust of wind picked up a ruffled piece of paper with a single stitch of warn out tape attached to it. On the sign were the words…

LOCK BROKEN

…

The meeting was dragging on far longer than John would have liked. The rest of Blue Team had been dismissed a while ago, Fred saying something about wanting to go to the gym, but the Master Chief had been instructed to stay behind for further debriefing.

Lasky was pleasant enough, but what was concerning was the female presence beside him. For the majority of the meeting he had been able to stare completely forward, almost robotic in how stiff he sat. However, about twenty minutes in his resistance failed him. He glanced over, his pale blue eyes drinking in the Commander's form, her body not hidden by bulky armor, but instead on full display in her tight black undersuit.

He looked her up and down, from her tight abdomen, to her perky breasts, to her pink full lips.

To his horror, Palmer caught him looking. She gave him a flirtatious, almost predatory smile, and winked at him. John immediately looked away, focusing his attention squarely back on Lasky who, thank the Lord, had his head buried in a datapad and so did not witness the brief exchange.

A single bead of sweat rolled down John's temple, and he too contemplated whether or not it was best to go to the gym after the meeting.

He had plenty of frustrations to work out anyway.

…

Cortana's too short shorts had joined the pile of clothes at the corner of the sauna, her full glorious naked beauty now free of all constraints. Furiously she flicked her fingers across her clitoris, the bright pink nub swelling in size with each stimulation, and occasionally slipped one or two pale fingers deep inside her pussy walls. Another hand cupped her breast and roughly pinched her erect nipple, sweat pouring out of every part of her body as the heat both in her groin and in the air absolutely consumed her.

She was swiftly reaching her peak. Reaching it far faster than she ever would have with John, her imagination allowed to run wild with the images of rough demanding hands, hands which took and did not ask, roaming all over her body. Doing with her as they please.

Yet, just as she was about to achieve her long denied climax, the door to the sauna creaked open, and Cortana's heart dropped to the pit of her stomach.

There, in the doorway, stood Fred 104, his mouth hanging loosely opened as he stared at the beyond beautiful woman in a full state of arousal. Legs spread, vaginal lips spread open by the tips of two of her fingers, nipples hard, cheeks flushed, glistening sweat all over her body.

Cortana could not determine for just how long Fred drank in the vision of her naked and lustful body, and her mind could not command her body to move. Instead her eyes began to wander, first at the silver streaks in his otherwise dark hair, then at the tight muscular frame that was his upper chest. His t-shirt stretched tight over him, revealing the outlines of every single muscle. Her eyes wandered further downward to his tight abs, all the while feeling the gaze of the Spartan upon her, her body's internal mechanisms preparing itself for what was about to come.

Down past the abs, Cortana let out a slight gasp. A large bulge stuck out of Fred's pants, the shorts tight enough that Cortana could see every detail of Fred's noticeably large member. It seemed to pulse at her, and Cortana felt a shutter of arousal flush through her system.

Finally, something seemed to break the spell that had left Fred dumbstruck, and he quickly adverted his eyes away and down towards the ground.

"I'm sorry. I should have knocked," he muttered, and began backing away. "I'll just…"

"Don't," came the word, and Fred stopped in his tracks. He brought his gaze back up to Cortana's naked and vulnerable form, and this time he did not possess the power to look away.

Cortana had no idea what had possessed her to say that. Every moral and social taboo screamed at her to tell Fred to leave. Questions of loyalty, fidelity, and guilt swept through her, and then they subsided, leaving only an aching feeling of lust behind. All the while she stared at the bulge in Fred's pants, her crotch growing harder with each passing second.

Her mind did not command her arm to move forward, her body making the decision that her mind could not. Her current mate was inadequate, and here was a virile male just waiting to step in as John's replacement. To do what he could not. She reached out and towards a far different life than she would ever have had with John.

Cortana ran her fingers on the outline of the bulge, and Fred silently cursed underneath his breath. She inched her body towards him, instinct commanding her now, and Cortana got down on her knees in front of the Spartan, gently rubbing his member with the palm of her hand through the fabric.

"We shouldn't be doing this," Fred muttered, almost pleading with her.

"We shouldn't," Cortana agreed, but did not stop her menstruations. Tentatively she grabbed the hem of Fred's shorts, and pulled them down. His cock bounced free, nearly hitting Cortana in the face, and her eyes grew wide.

She grasped the base of his cock, and slowly began sliding her hand up and down the shaft, muttering to herself, "So much for always being second."

"What?" Fred asked, his breath hitched.

Cortana looked up at him, her electric blue eyes brimming with lust. "You've always been second to him haven't you?" she asked, jerking his cock all the while. "Always second best." Her free hand reached up and she dug her nails into his inner thigh. "Maybe you should just take what you want."

"This is wrong," Fred said, his fists curling up into balls.

"It is," Cortana agreed, but still did not stop stroking him.

Fred squeezed his eyes shut, and when he opened them they were filled with newfound determination. "Fuck it," he declared, and stepping into the heat of the sauna slammed the door shut behind him.

Fred threw his back against the wall, any feelings of guilt leaving him far behind as Cortana picked up her pace. When he felt the warmth of her mouth envelope his cock he let out a loud moan of pleasure.

Cortana bobbed her head up and down, the tip of his engorged member hitting the back of her throat. Even then she was still only taking half of him, and Fred was growing impatient.

Without warning he grasped the back of her head, hands grabbing hold of fistfuls of hair, and began roughly shoving her mouth down further on his cock, thrusting with his hips all the while.

Cortana choked and gagged as she struggled for air, her eyes watering as Fred's cock touched places that John's had never been able to go. Yet, even as she struggled with her gag reflex, her crotched boiled with mounting desire.

When it finally became too much Cortana pushed her mouth off of Fred's cock, and immediately began coughing.

"Always second place?" Fred growled, causing a twinge of pleasure to roll up Cortana's pussy. "Should just take what I want? Fine." He picked Cortana up and slammed her up against the wall, the entire sauna shaking as a result. "I'll take what I want."

Cortana covered his mouth with hers, all thought escaping her as she tugged at his shirt, finally ripping it off. Fred's shorts hit the floor, and Cortana wrapped her arms around him, hands and nails going crazy on his back, her breasts pushed up firmly against his chest.

"Do it," she pleaded with him. "Do it. Just do it."

Fred aligned his cock and thrusted upward, Cortana letting out a cry as he penetrated. He fucked her up against the wall, Cortana's legs wrapping around his waist, her pale feet bouncing in the air with every thrust. The heat and humidity of the sauna wrapped itself around their bodies, drenching both of them in thick sweat, their bodies making loud slapping noises as Fred continued to fuck her. To use her in any way he saw fit.

Cortana loved it, uncontrollable moans escaping her lips.

She held onto Fred as tight as she could, putting her chin on his shoulder as he drilled her into the wall, her hair now wet and slick with sweat.

Fred seemed to tire of the position and let her down. He forcefully grabbed Cortana by the neck and bent her over, pushing her face first up against one of the windows. He positioned himself behind her, rubbing the very tip of his cock against her entrance.

Cortana pressed her forehead up against the cold glass, relishing the moment when Fred would finally thrust in. But, when she looked through the glass at the outside gym, a stone fell into the pit of her stomach.

There was John by one of the treadmills, his face betraying no hint that he had any idea of what was going on mere feet away from him. He started the treadmill up and began running at a steady pace directly facing her and Fred.

"Fred," Cortana said. "Wait. He's right there."

Fred looked up at John, and then back down at Cortana's swaying heart shaped ass.

"Fuck him," he said, and thrusted in as deep as he could go.

Cortana bit her arm to keep herself from crying out, Fred taking her just as roughly as before, but with more of an effort to keep quiet.

Cortana looked up, could see John running on the treadmill, a sweat just beginning to form on his brow. Completely unaware of what his girlfriend was doing even though he was looking straight at her. The full reality of the situation, of what she was doing, finally hit her.

Cheating, infidelity, adultery. She was doing all of those things, yet just at the moment of realization something happened that washed all of her guilt away in one instant.

Cortana came. She came hard, juices dripping onto the floor, her lower body contracting and tremors moving up and down her arms and legs. Cortana bit down on her arm almost hard enough to draw blood. The orgasm passed, and Cortana's legs lost their strength, and Fred withdrew from her, leaving her trembling and shaking against the sauna wall.

She spared one last long look at John, and then turned her back away from him, gazing hungrily at Fred who was now sitting down on the bench.

Her past behind her, her future in front.

Cortana attacked Fred, nails scrawling across his chest. Fred brought Cortana onto his lap and quickly reentered her, holding onto her hips as Cortana bounced up and down.

Fred buried his face into Cortana's breasts and greedily began to feast, dark hickies being left in his wake. Marking her as his. Marks that she would never be able to hide from John. Marks that ensured there was no going back after this.

Cortana bent down and whispered into Fred's ear. "You want me?" she asked, nibbling on his earlobe. "You want to make me yours?"

"Yes," Fred groaned. Would have said anything she wanted.

"Then take me," she demanded, biting and leaving kisses along his neck. "Steal me. Steal me from him."

Fred let out a deep groan and Cortana moaned as both increased their pace. Their bodies eager to consummate their sinful union. At that precise moment Cortana would not have cared if John had walked in on them right then. It was far too late. Far too late for John.

She felt Fred begin to tense up, his cock growing larger inside her. He forced Cortana's hips down and held her close to him as he pumped what seemed like an endless stream of warm cum deep inside Cortana, her womb greedily taking as much of the seed as it could, finally content in having found a deserving mate. She came along with him, their shared orgasm bonding them together in a marriage that nature herself presided over.

Cortana and Fred breathed heavily, both of them coming down off of their respective climaxes. Fred whispered in her ear. "So am I still only second best?"

Cortana giggled. "No, far from it." Her fingers began to trace circles along his muscular shoulder. "I'm going to have to put in a request for a room change."

"What about John?" Fred whispered back.

"What about him?" Cortana asked. She leaned back and smiled proudly at him. "You did it. I'm yours now."

Fred smiled at her. A warm boyish smile. The two began to kiss passionately.

Outside John shut off the treadmill and moved on to the weights, setting up for a bench press.

Ear buds were in his ears, the briefings of other fireteams on Infinity playing loud enough so that the rest of the world was all but mute, including the renewed moans of his now ex-girlfriend a few feet away.

As he began his reps, Cortana and Fred began to make passionate love once more.