"There's something I need to tell you."

The look of panic that momentarily flashes across Merlin's face is almost enough for Arthur to bail. Arthur hates seeing Merlin hurt, and he'll never live with himself if he's the cause of Merlin's pain. So there's absolutely no way he can go through with this. Then again, Arthur forcefully reminds himself, if he backs out now, it will only get worse later on. The quicker he gets this over with, the quicker it will all be over. He takes a deep, calming breath. You can do this, Pendragon. You don't have a choice.

But he can't do it, it isn't possible. He is not physically capable of looking Merlin straight in the eyes and saying-

"We need to break up."

The look on Merlin's face will haunt Arthur for years to come. Time slows down to a crawl, the sights and sounds of the park grinding to a halt around them, and Arthur imagines he can hear his heart shattering as Merlin's hand goes slack in his.

"What?"

"We need–" Arthur stutters to a stop, then tries again. "We can't be together anymore."

"Oh."

That's all he says. Just a small, broken little "oh," as Merlin withdraws his hand from Arthur's grip, letting it hover in the air somewhere between them uncertainly before letting it fall to his side. His expression shutters, his eyes brimming with confusion as he stares at Arthur, waiting for an explanation. Arthur can't bring himself to look away from the emotion brewing in Merlin's eyes. Those eyes, the very first thing about Merlin he fell in love with. The eyes that were warm and friendly when they first met, back when Arthur was home fresh from Afghanistan, the sound of gunshots still ringing in his ears.

He hadn't wanted to go to the stupid dinner. All he wanted was to spend a quiet evening lying about his flat, watching mindless television with a plate full of microwaved leftovers. But Morgana had insisted, kicking down his door and threatening to drag him along by his ears.

"You've been home two months already and you haven't left your flat in a week," She had said, hands on her hips, eyeing the pile of dirty takeaway boxes littering the coffee table. "It's time you got out, Arthur, met some new people, got your social life back."

It really hadn't been worth pointing out that he never had a social life to begin with. All his childhood friends were really only the children of his father's colleagues, friendships built on convenience rather than genuine fondness for each other.

Morgana wasn't hearing any of it, and soon Arthur had found himself squeezed beside her in a booth in a pub that was far too dim and far too crowded for his liking, surrounded by people he didn't know.

Then a man showed up, pale and lanky with the bluest eyes Arthur had ever seen.

"Merlin!" Morgana had greeted enthusiastically, "You're late! Merlin, this is my brother, Arthur. Arthur, dear, Merlin's a good friend of mine."

Merlin had smiled a smile that took up his whole face, as if he was actually happy to meet Arthur. He leaned over to shake Arthur's hand, and Arthur noticed the way Merlin's smile was making little wrinkles on the corners of his eyes. He fell in love on the spot.

Now Arthur can't take it, the fact that he is the cause for the pain in those eyes, and he wants nothing more than to take it all back, to surge forward and kiss away the unshed tears before they fall. Instead, he takes a shuddering breath and does his best to ease the blow, cursing his inept way with words.

"I'm sorry," He starts, wincing at the hollow sound of his voice. "It's for the best. I love you, but I–" Arthur stops. How can he explain this? "I've been called back. They need me to fight, back in Afghanistan. I got the letter a few days ago."

Merlin is quiet, then: "So?"

"I'll be gone eighteen months," Arthur explains, wishing, desperately, that Merlin will understand and stop looking at him like that.

"That's a long time." Merlin says quietly, "But what does that have to do with us?"

Arthur opens his mouth, but he can't think of a reply. So he stands there, frozen, furiously stamping down the urge to grab Merlin and tell him to forget he ever said anything.

Finally Merlin breaks the silence with, "Do you think you're going to die?"

"No!" Arthur replies immediately. "Well, maybe, but it's not just that. It's because you deserve better, Merlin."

"I deserve better?" Merlin repeats, his eyebrows darting up at the words. "What the hell does that mean?"

"Eighteen months," Arthur repeats, forcing some small amount of firmness into his tone. "That's longer than it sounds like, trust me. I can't ask you to wait that long."

"I'll wait for you," Arthur winces at the lack of hesitation in Merlin's reply. "However long it takes."

Arthur lets out a gruff sound of frustration. "Merlin–"

"Unless you're afraid of me cheating? Losing faith in you?" Merlin questions, taking a step closer, taking hold of Arthur's hands once again in an iron grip. "Because you can go ahead and botch that idea. I'll wait for you."

"No, you don't understand!" Arthur says, trying vainly to pull out of Merlin's grasp. "War is a different environment. There's violence and fear and it's brutal, and It's going to change me. No matter how much you think you love me now, I'm going to change out there. I can't ask you to wait a year and a half for a man you won't even know."

"But–"

"A year and a half of your life," Arthur says firmly, "It's too much to waste on me." He brings their joined hands to his mouth, tenderly pressing his lips to the backs of Merlin's knuckles. He lets his eyes flutter closed, so that he doesn't have to look at the heartbreak on Merlin's face.

"I still love you," Arthur murmurs, lifting his eyelids but keeping them trained on Merlin's nose, or his chin, anything but his eyes. "And I know you love me, but you'll get over it. You'll find someone else, and I want you to be happy with them."

"Arthur–"

"Goodbye, Merlin." Arthur straightens up, dropping Merlin's hands and turning away. The loss of contact is like a dam opening, bringing the tears rushing, boiling hot, to Arthur's eyes. He blinks and starts to walk.

He doesn't make a single step before one hand is grabbed again, and Arthur is forced to turn around. As he does, he can't stifle the involuntary gasp at the sight of Merlin, holding Arthur's hand in both his own, having dropped to his knees on the ground.

"Don't," Merlin pleads, eyes brimming with his own unshed tears. "Please."

Arthur shudders through a sob. "I told you, Merlin–"

"Marry me."

The two simple words hit Arthur like a freight train, expelling the wind from his lungs and knocking him flat on the ground.

"What?"

"Marry me," Merlin says again wildly, staring up at him with desperate, shining eyes. "I don't care if you're going away, I love you and I'll wait for you. I promise."

"Merlin, don't do this," Arthur chokes out, voice breaking. "It's too much. I'll be gone and you'll be lonely and some bloke will come along to comfort you, and you– you might–"

"Do you honestly think I would do that?" Merlin says harshly, crushing Arthur's fingers in his own. "Do you really think I'm capable of something like that? There's no one else, Arthur, I couldn't– not with anyone else, only you. So please."

Arthur is at a loss for words. He is aware, dimly, of people watching them, in the middle of the park on a bright sunny day. It feels awkward; Merlin on his knees with one of Arthur's hands in both of his, while Arthur's other hand hangs at his side, useless. But all he can see is Merlin's eyes, pleading and earnest and bluer than blue. Desperate.

They flicker, for a moment, as Merlin seemingly looks to the ground to gather courage before looking back up. "Do you remember that first time I told you I loved you?" Arthur nods, numbly. "In your flat, that morning before you knew I was awake, I saw you, touching the dog tags on your bedside table. I couldn't see your face, but I could see, I could tell what the war meant to you. I knew you had been through things that maybe you would never talk about, but that was okay, because it made you a better man and you were mine. That was when I knew I loved you and I told you so. Do you remember that?"

"Yes," Arthur says. Tangled up in the sheets together that morning, lying in the early sunlight with Merlin a warm, comforting mass beside him, Arthur was happier than he'd been in years. For the first time since he began his inactive service, life seemed simple. In that moment, nothing mattered. Not the war, not his father, nothing except Merlin lying beside him.

"I meant it," Merlin says, "I meant it then and I mean it now. I don't care if the war changes you, I love you no matter what. I swear to you, right now, nothing can change that. I wouldn't give you up for the world."

He surges forward then, pressing a kiss to Arthur's knuckles, mimicking the way Arthur kissed Merlin's minutes ago. But this kiss isn't a goodbye, it's a plea. Don't go. Stay with me.

"You would really wait for me? You love me that much?"

Merlin raises his head by a fraction, locking his gaze with Arthur's. When he speaks, his lips brush the skin on Arthur's hand.

"I would wait a thousand lifetimes for you, Arthur."

Arthur doesn't trust his legs to hold him up anymore, wobbly as they are, so he sinks down to the ground until he's at eye level with Merlin.

"Okay," He says, his voice barely more than a cracked whisper. "Okay, Merlin. Okay."

"Okay?" Merlin parrots, a happy, uncertain smile blooming across his face through the tears. "So you'll marry me?"

Arthur gives a shaky nod and scoots closer, bringing his hand up to cover Merlin's in both his own. Tears are streaming freely now, from both their eyes, and Merlin laughs as he laces his and Arthur's fingers together. Somewhere they can hear the "aaw's" of a few passersby.

"I love you," Arthur says, grinning.

"I love you too, you bloody idiot," Merlin says, kissing Arthur softly. "Don't you ever–" another kiss, "–try anything like that–" kiss, "–ever again."

"I'm sorry," Arthur says, returning each kiss with fervor. "I'm so sorry. I thought it would be for the best, that you deserved better than me."

"I don't want anyone else," Merlin promises, "Just you."

Arthur huffs out a laugh. "I believe you."

Arthur untangles their hands so that he can wrap his arms around Merlin, clutching him tightly to his chest. Merlin does the same, so that they are holding on to each other in the middle of the sunlit path. Arthur's knees are protesting from the scrape of gravel and the awkward kneeling pose, but he can't bring himself to care about anything but the man in his arms.

"So," he says finally, pulling away to look Merlin in the face. The tears have dried, and now Merlin's eyes are truly sparkling. "Marriage?"

Merlin laughs. "Marriage. As soon as possible."

"Like now?"

Merlin's eyebrows once again shoot up in surprise. "Now? Right now, right now?"

"Right now," Arthur confirms, smirking. "You proposed rather suddenly, and it is Sunday, after all. Unless you have any objections?"

Merlin's mouth hangs agape for a moment, before he scrambles to say, "No! No, right now's good, let's go!"

Arthur chuckles. "You're eager."

"You tried to break up with me," Merlin points out, "I think my eagerness is justified."

Arthur laughs and kisses him again.