John supposed it all started with his father, if you really wanted to delve to the root of the problem.

Father. The title had been spoken in a detached, impersonal manner since John was a child. The man had left his mother a mere three months before John's birth. Abandoned her with two children- one still growing in her womb, the other barely a toddler.

His mother rarely spoke of the matter, or of his father in general. What John knew about him, he'd gleaned through snippets of broken conversation during his youth. He was an enigma, shrouded in half-truths and mystery. John hardly knew anything about him, and yet, the man had utterly consumed his thoughts as a child.

Who was he? What did he look like? John had seen pictures, of course. Photos that his mother had tucked away in a shoe-box on the tippy top shelf of her closet and John had secretly claimed for himself. But what did he look like? Did his eyes crinkle when he smiled, like his mother's did? Did his skin glow golden from the sun, or did it go all freckled and speckled, like Harry's? How did he walk? Was his hair as soft as it looked in the pictures? What did his laugh sound like?

Sometimes, when John lay sleepless in bed at night, he would close his eyes and try to imagine his father. He had spent literal days of his childhood attempting to build the man in his mind, piecing together every scrap of information he'd ever collected about him. He kept his eyes squeezed tightly shut for hours at a time- because once he opened them again, the illusion would always shatter and he'd be left with nothing.

And above anything else, there was that all-consuming question. Did his father ever think of John? Even a little, tiny bit? Did he even wonder about John a fraction as much as John wondered about him?

As he grew, his father became less of a gaping hole in his life and more of an afterthought. John tried not to think of him if he could help it. He went on and lived his life and tried to make something of himself. But even as an adult, the thought of his father made John hurt and ache in all the wrong ways.

And that was why, even though he'd never met the man, John considered him the start of it all. The initiator of the one constant truth in his life- that those he loved would always leave him.

Sherlock was an untamed force. Flighty, reckless, and thoughtless of anyone but himself. He was everything that John had spent the entirety of his life trying to avoid.

Living with the man was a dizzying experience. One minute, he was a whirlwind of frenzied activity. The next, he would lay listless on the couch for days on end. It was the highest of highs and lowest of lows with Sherlock. He was a walking contradiction. Both brilliant and completely clueless. Careless yet meticulous. Endearing and hopelessly infuriating. A lovely disaster.

Sherlock made his head spin and his chest ache, and John had never felt more alive.

He met Olivia at university. It was a fairy-tale sort of encounter- the type that they'd tell their friends about for years to come. They met in a campus coffee shop, making coincidental eye contact from across the cafe. John worked up the courage to approach her and exchange phone numbers after a week of fleeting stares and shy smiles.

Olivia was everything John thought he wanted in a partner. Kind and genuine and level-headed. She was studying to be a nurse. She had two pet cats. She liked to read, do yoga, and played the piano. She reminded John of his mother, in the best sort of way.

And for a time, they'd been happy. They dated for two, going on three years. Shared a flat. John had grown comfortable and complacent in their relationship. Had taken it for granted that he would marry Olivia. He picked out a ring and everything, with grand plans to propose after graduation.

In the end, Olivia had been the one to break things off. Matter of factly, she had sat him down on their couch and proceeded to list all the reasons why things weren't working out between them. Every reason seemed petty and senseless. John realised, too late, that she had fallen out of love with him a long time ago.

Perhaps, John theorized, they had been too similar in personality to make things work. Both easy-going and practical and a touch too aloof. There had been no fire, no real passion in their relationship.

But it was just an idea. Something to placate John's hurt and heartbreak. He had really thought he'd loved her- that she was the one. But when he thought about it, he couldn't even say when their love had begun to die.

Living with Sherlock was a trial in patience. The day he moved in, John discovered one of the man's experiments festering in the fridge. Beakers of various liquids, each with a severed human finger floating inside, tucked neatly between the milk and eggs.

"To test the decomposition speed of household cleaners on human flesh, of course," Sherlock had replied when John asked what the project was for, as if were the most obvious thing in the world.

Disgusted, he had politely asked Sherlock to move the beakers elsewhere. He discovered them under his bed, three weeks later, when the smell grew too bad to ignore.

John decided that the fridge was the lesser of two evils. Nowadays, he pointedly moved any bottles of acid or decaying body parts he found to the lowest shelf, but didn't bother the experiments otherwise.

Sherlock was a decidedly ungracious flatmate. His transgressions went far beyond normal flatmate qualms such as undone chores or unwelcome overnight guests. Sherlock shot literal bullet holes through the walls when he was bored. He played screeching violin sonatas at three in the morning. He left pieces of molding bread scattered round their flat, 'for the sake of science, John'. He had once rifled through John's wardrobe and stolen each and every one of his left socks, for reasons still unknown.

He was infuriating. Ridiculous and brash and unabashedly apologetic about it.

However, on rare occasions, it was as though John didn't have a flatmate at all. Those were the dark days, when Sherlock went unnervingly quiet and grew absent. When he curled up on the sofa and just lay there, glassy eyed and slack jawed and lifeless.

When Sherlock was like this, it terrified John. The silence was wholly unnerving. Nothing he did or said could rouse Sherlock from these sort of spells. John would lie awake in bed at night, unable to sleep from the quiet of it all.

And when Sherlock returned to his normal, inconsiderate self, hours or days later, John would find himself inexplicably relieved beyond words.

John had been very close with Harry, at one point in his life. Growing up, the two had been nearly inseparable, being less than three years apart in age. They shared a bedroom until they were nearly teenagers. It was a bit of a necessity, in their tiny two-bedroom house, but neither of them had ever minded. Two peas in a pod, their mother endearingly called them.

They spent their youthful summers running barefoot through the backyard. Played all sorts of silly games. Drew chalk drawings on the pavement in the daylight and caught fireflies once it turned to dusk.

They whispered secrets to each other from across their bedroom at night. John had been the first one Harry told when she realised she liked girls. He was eight, and Harry nearly eleven, when she'd whispered this secret to John under the safety of darkness. Told him all about her crush on the pretty red-head neighbor girl.

Their relationship grew strained when Harry entered high school. She was suddenly distant. Rebellious and moody, with no time or sympathy for John. She swore at their mother and slammed doors and came home after midnight reeking of cigarettes and alcohol.

She dropped out of school a year before graduation. Packed her things and moved across the country to live with her girlfriend without even saying goodbye.

She left John to deal with the aftermath of her actions. Their mother was a wreck. Sobbing and hysterical and inconsolable for days. John left Harry a distraught voicemail, begging and pleading with her to come home. The next week, when John tried to call again, the number had been disconnected.

Over time, John and Harry resumed contact. They texted each other now, exchanged cards on birthdays and Christmas, met up for dinner once or twice a year. But it was all obligatory. A forced and strained relationship. Life had made Harry jaded- she was discontent and angry with the world. A shadow of her former self. John's sister had abandoned him, in every possible sense.

Sherlock had a thousand different ways of saying John's name. A secret language of Johns. Each one unique, with its own infliction and hidden meaning. John quickly became an expert at reading Sherlock's mood, solely based on the way in which he said John's name.

"Jooooohn." Dangerously bored.

"John!" Near frenzied excitement.

"John-" A distracted summons.

"John..." Total exasperation.

"John."

Reverence. Exaltation. Awe. On those rare occasions when John managed to surprise and outwit Sherlock.

When Sherlock said his name this way, with his silver eyes wide and dazed, John felt like his chest might just burst.

His mother got sick the same month John left for Afghanistan.

She told him over Sunday tea, transitioning from polite small-talk to life altering revelation seamlessly. So straight-faced and resolved about the matter that it made John physically shudder.

Pancreatic cancer. Three to six months.

John was a doctor. There was no need for questions. He knew the cancer was incurable- quick-spreading and ultimately fatal. It was a worst case prognosis.

He tried to postpone his deployment. His mother had protested and insisted that he go regardless. They rowed about it terribly, but his mother had been unrelenting. Heaven be it on her if she was a burden to her own son.

In the end, it hadn't much mattered. The army denied his request. Though they had graciously granted him a week's leave, four months later, when his mother ultimately died.

The funeral was a brief affair. Attended by a handful of estranged family and friends. John felt surprisingly numb as they lowered his mother's casket into the fresh-turned earth. He waited and waited, but to his surprise, the tears never came. He flew back to Afghanistan the next day, stoic and hardened.

Two weeks later, he'd been shot. Laying in the hospital bed, feverish and nearly blind from pain and so alone in the world, the tears had finally come.

John fell in love with Sherlock slowly, naturally- like breathing, or falling asleep. So automatic that you didn't even realise it was happening until it was already over with.

He hadn't realised it himself until it was too late. Until after Sherlock had jumped and dropped like a stone from the roof of St Bart's, hitting the sidewalk with a splat and oh god- the blood, and oh god- Sherlock, no-

He'd been unable to sleep for days and days, after that. Every time he closed his eyes, he saw it happening all over again. The flailing and the screaming and the bleeding, and Sherlock's dead eyes, glassy and unseeing-

And the funeral. God, seeing his body laid out like that, all pale and stiff. Once he was home and alone, John had sobbed like a baby.

When had he fallen in love with Sherlock? John couldn't say, really. Somewhere between morning tea and late night takeaway. Somewhere between chasing criminals down dark alleys together and those impressive, ridiculous deductions. Somewhere between dark hair and long limbs and unearthly blue eyes.

God, he was gorgeous, John realised. Had been gorgeous. And brilliant and lovely and everything. But all that hardly mattered now, did it?

And then, Sherlock rose from the dead, like Lazarus rising, and it was too little too late all over again.

Mary. Oh, Mary. Quite contrary, just like the rhyme said.

But John had loved her. Really, truly loved her. If Sherlock was a force, Mary was an inferno. She threatened to burn him up- to consume him entirely. John relished in it.

She brought purpose back to his empty life. Helped him grieve, and cope, and move on from the overwhelming loss that was Sherlock. And when Sherlock returned to the land of the living- inciting a whole different kind of hurt- well, she'd helped him through that too.

John was certain that Mary knew. She was uncannily observant, in that way. She studied John and Sherlock together with thoughtful, keen eyes. Even when John put on a face and averted his eyes and tried to bury his traitorous feelings, Mary just smiled.

She had never said a word about it. After all, Mary had her secrets too. She and John could be liars together and live a happy life of make-believe.

It had been bliss, for a time. And then Mary left him too.

John held her as she died, all clammy and shaking and slick with blood. He watched as the life left her eyes, as her limbs went limp and her body grew cold.

There was no resurrection for Mary. No miraculous rebirth, like there had been for Sherlock. Mary was dead and gone for good, and John had never been so alone.

It happened on a Tuesday.

Nearly four months had passed since Mary's death. John had moved back to Baker Street two months prior, if only to escape that empty house and the memories that still lingered there.

It happened over tea.

John made it, like always. His own black and Sherlock's weak and milky with too much sugar- just how John knew he liked it, though Sherlock would never admit to it.

It happened suddenly. Blink too fast and you'd miss it.

One minute, John was sipping from his mug. Sitting sock-less at the table, still dressed in his wrinkled pajamas, watching the morning sun creep into the kitchen. He was calm and comfortable. Content in a way he hadn't been in months.

Across the table, the sunlight cast a golden halo on Sherlock's dark hair. The man took a long drink from his own mug, giving an appreciative 'hmm' and licking his lips in a way that set John's heart pounding. Sherlock looked up and met his eyes. Unthinking, John favoured him with an unbearably fond smile.

Oh. That feeling, again. He hadn't felt that way in ages. Not since Mary died. This time, John recognised it for what it was.

And so did Sherlock. In the next moment, the man slammed down his tea and rose from his seat, eyes wide and face pale.

"John."

John tensed upon hearing his name spoken like that. Oh, shite. Oh, god no. He never meant for Sherlock to find out, never meant to feel this way ever again. Not after Mary- not Sherlock, oh god-

Sherlock, astute as ever, sensed John's rising panic. Making his way round the table, he fluidly plucked John's mug from his trembling hands.

"Oh, John."

Sherlock's voice was reverent and horribly tender. John shuddered.

Sinking to his knees, Sherlock grasped John's face in his hands, eyes flickering from here to there, calculating. Reading John like a book. John closed his eyes- a feeble attempt at escape.

He felt Sherlock's fingers tighten minutely on his face. "How long?"

John flinched at the question, and kept his eyes tightly closed.

Sherlock's hands migrated from his face to his shoulders and squeezed hard. "John."

Heart pounding, John opened his eyes. Sherlock stared at him, unblinking, eyes wild and dilated and feverish.

"John. Answer my question. For how long have you loved me?"

God, Sherlock really had no sense of decorum. But the question was out there now- naked and bare, and there was nowhere for John to hide. Sherlock knew. God, he knew.

"Awhile," John admitted, hating the way his voice shook.

Sherlock gripped his shoulders tighter and shook his head back and forth frantically. "No. Not good enough. I need specifics, John. I need data. When exactly?"

"Jesus, Sherlock, I don't know." John shrugged his shoulders abruptly, knocking Sherlock's hands away. "What does it matter?"

Sherlock just sat there, kneeling on the floor, arms hanging limply at his side. "It matters," he replied after a long moment, sounding so forlorn that it made John's chest hurt. "It means everything, John. Why don't you understand? I have to know. How long? How long have I been blind to this?"

John shrunk back in his chair. Sherlock looked absolutely ragged. Desperate in a way John had never seen him before. "A long time," he admitted finally. "Since before- before Mary. And before the jump, probably. But that was when I first realised it."

Sherlock exhaled shakily, sinking back to sit on his heels. "Oh," he said, rather brokenly.

John gripped his pajama bottoms tightly, heart sinking. "Sorry. I'm sorry, Sherlock. It doesn't matter. I didn't mean for you to find out. It doesn't matter-"

"Stop saying that," Sherlock interrupted, shooting upright once more and grabbing John's hands in so tight a grip his fingers ached. "Stop saying things that we both know you don't mean. You love me."

"I-" John stuttered, his hands twitching in Sherlock's grasp. "Well-"

"You're an idiot, John Watson," Sherlock breathed. And before he could protest, Sherlock flung his arms around John and pulled him into a tight, frantic embrace.

John's head spun. Sherlock smelled faintly of cloves and stale cigarette smoke. He could scarcely breathe. "I- Sherlock, you-?"

Sherlock pulled him more firmly against his chest. John could hear his heart racing through the thin fabric of his shirt. "You see, but you do not observe, John."

"Oh," John said simply, suddenly understanding. "You love me too."

"Yes."

John tensed, his mind racing. God, he couldn't do this. Not again, not after Mary. "Sherlock- I-" John stammered. "I can't. We can't-"

"Quiet," Sherlock commanded sharply, threading his fingers through John's hair. "Of course we can. Don't be daft. Don't make excuses- not about this. I love you, and you love me back. There's nothing more to be said."

Sherlock's voice was firm and resolved. He made it sound so easy. But things were never quite so simple as that.

"You'll ruin me," John confessed. He ached from the truth of the words. But as he spoke them, he clutched Sherlock tighter, turning his head to bury his face in the crook of the man's neck.

"Possibly," Sherlock agreed from somewhere above him, carding his fingers through John's hair in a way that had him tingling all the way to his feet. "Likely, we'll ruin each other. A mutual, reciprocal destruction. But we'll rebuild each other too. Time and time again. I'd fix you a thousand times over, John. If you'll allow it."

"Oh god." John allowed his body to go slack against the other man's. "Sherlock."

Sherlock hummed in response, ghosting a hand up and down John's back.

"Don't leave me," John pleaded, whispering, voicing his greatest fear aloud. "Not again. Not you too."

"Never," Sherlock promised fiercely.

And for perhaps the first time in his life, John Watson felt whole.