He should've known playing with fire was going to be disappointing.
After all, Sherlock Holmes was not an ordinary man. What he felt, what he had the capacity to feel, experience, and what he chose to indulge or placate was significantly less and different than the majority of the population.
Nowadays, most people indulged near immediately in their cravings, whatever they may be. If they were feeling peckish, they'd grab a bite to eat; if they felt like getting a slice of chocolate cake, they would, provided they could procure the funds and/or the ingredients. If they were thirsty, they'd grab a drink; if they were tired, they'd drink energy drinks until they could sleep, or they would immediately drift into slumber. If they were horny, they found some way of gratifying that urge.
Sherlock was an asexual being. Sherlock didn't feel the urge to have sex. Sherlock abstained from eating more often than not, slept sparsely, and only when his body forced him to, and drank little alcohol. His drug use ("abuse," John would scold) merely stimulated his mind when nothing else could. It was a necessity, an escape from reality's unfortunate dullness.
John Watson was, simply put, Sherlock's opposite. Yes, yes, there was all of that "heart versus mind" nonsense he overheard Mrs. Hudson gush about frequently to her friends, and of course there was the appearance differences: John being short and blonde, Sherlock being tall and raven-haired. Sherlock dressed for elegance, John for comfort and practicality. Sherlock cared about nothing, John everything.
John indulged his whims, desires, needs, whenever he could, whenever was appropriate. Sherlock rarely indulged, his only "indulgence" being the drug use, and that, he'd argue, was less of an indulgence and more of an attack (honestly, they'd thank him later for toning down his boredom; they knew how bad it could be without them).
So when Sherlock Holmes began feeling a strange craving for John Watson, his immediate reaction was to ignore it. He assumed the urge would surrender quickly; after all, it was beyond logic, beyond practicality, beyond reality, but it fought against suppression. His thoughts flew to John whenever they pleased. The army doctor haunted his steps, his mental rabbit-trails, his mind palace. In return for suppression, this urge splattered bright red, passionate, paint all over his mind palace, covering everything it could.
Mine, it seemed to hiss, all mine.
And the trouble wasn't that John Watson held such a claim, or that the urge was in existence, or that Sherlock couldn't do anything about it but panic and wonder when he'd fallen, when he'd stooped so low, when such shame and disgrace tarnished his existence; the trouble was that Sherlock sensed the same desire in his flat mate.
It was so obvious. Painfully obvious. Screaming-in-a-silent-room obvious. Anderson obvious.
It seeped into every conversation, stained every touch, scandalized every shared glance. It ruined Sherlock's thinking, ruined their dynamic. It took their comfort and stretched it taunt, mocking them for falling still, for feigning ignorance, for ever beginning this damning friendship.
Sherlock Holmes didn't have friends, and that was why.
They never ended well.
Sherlock learned this well over the years. People had the tendency to respond to his intense apathy by amplifying their emotions. Everyone who ever met Sherlock Holmes and tolerated him beyond some form of obligation either hated or loved him. There was no in-between. They either wanted him writhing in pain or pleasure, screaming or moaning defeat, all by their hands.
He had to hand it to John: he really tried to suppress and slaughter his desire. Sherlock saw it frequently, how much John loathed loving him like that, how much he longed for a simpler time, where he could exist alongside Sherlock without his mind wandering and blood rushing, racing, burning. Sherlock saw him trying to rewind, to retrace his steps and fix this irritating glitch.
He saw John's defeat, slow and crippling, saw the talk coming miles and miles away.
He hated John's nervousness, hated the upcoming obvious confession, hated how much he longed to hear the words, to know his mind wasn't lashing out at his own brutal suppression by casting his longing upon John.
"Sherlock," John began, voice crackling, wavering, reaching out for Sherlock, begging for forced silence.
Sherlock sighed and granted the unspoken request. "John, is everything alright?"
Nope. He couldn't (wouldn't) do it, admit his understanding, his awareness. Damn him, damn John Watson for ever making him feel like this. Damn him for so obviously pleading for respite, release.
John blinked, glanced away, fiddled with the glass of wine in his hands. "No. You know it isn't." Sherlock refused to respond. "You know," John continued, "and you want me to do the talking." A pause, a heavy sigh (Dear God John just get on with it). "I think we should stop pretending that friendship is all we can handle. I think we should try to be more."
Sherlock narrowed his eyes. So many options, so many possible routes, so many reasons for his heart racing and his hands twitching. "I know. You haven't been subtle."
"Neither have you," John bit back. Sherlock resisted the urge to snort disdainfully and end the conversation.
"Your point?"
John glared. "Just bloody tell me what you want from this, from me."
"I want you to make up your mind," Sherlock snapped. "What do you want from me?"
"I want you."
Sherlock Holmes should've known there was something wrong with it from the moment it started.
Because when he damned himself, damned this asexual being he should've (was, no, is) been, damned himself to a life chained to another mortal, John Watson didn't do anything but smile faintly, innocently, painfully, and look away.
The first, second, third, fourth outings were pleasant enough. When it was obvious there was no purpose for going out to eat or strolling through town, no criminal investigations or scientific inquiries, they enjoyed themselves well enough.
What Sherlock feared most of all was that conversation would run dry, and they would be left in awkward silence, unsure of everything. It was uncharted territory for Sherlock (he'd never been in a proper relationship before) and a relatively new experience in John's life. When he found that conversation wasn't uncomfortable, that things were as easy between them as they'd always been, Sherlock relaxed.
Beyond that, however, there was nothing. Sherlock was quick to find that nothing about this was pleasurable, nothing about this was any different (yet) than it always had been, and he didn't want it to intensify. People around them seemed to relax because they had, but no discernible signs appeared that they registered the change in their relationship.
It was obvious that John didn't like that. It was (supposed to not be) obvious that Sherlock did.
Nonetheless, when the opportunity presented itself, Sherlock reached for John's hand and clutched it, partly out of curiosity and partly out of a desire to appease him. John smiled, and they continued walking.
Sherlock knew there was something wrong, then. Their connection wasn't comforting or electrifying or anything like that.
It was cold. It was empty. It was claustrophobic.
Sherlock felt his icy demeanor melting, melting melting melting until his features were disfigured, his skin repulsive, his senses flawed. He couldn't stand to look at himself in the mirror, couldn't look at his hands, couldn't meet John's warm, happy gaze with truth.
Sherlock Holmes was not meant for sentiment. Sherlock Holmes was not meant for fire.
He was going to drown in a sea of his own released emotions, and John wouldn't be the one saving him.
John Watson would be the one dragging him under.
Sherlock lay on the couch, John resting in his lap, as they watched some bland show John insisted was worth paying attention to.
(Spoiler alert, John: it wasn't.)
Sherlock didn't know how to sit with John crushing his body into the couch. He didn't know whether he ought to cradle him in his arms, whether he was supposed to amuse himself by running his fingers along John's skin, through his hair, whether he was supposed to start kissing his skin.
Kissing John seemed to be too extreme. Perhaps he just needed more time to adjust to the idea of becoming so intimate with John, because the thought of it, of what could result in him peppering John's neck and shoulders with kisses, what could follow, repulsed him, repulsed him far more strongly than he expected. However, sitting there unresponsive wouldn't end well, either, so Sherlock settled for running a hand absently through John's hair.
John seemed to melt under Sherlock's touch, and the thought filled him with a tiny sense of satisfaction. This was something Sherlock didn't mind; caressing the doctor, his doctor, wasn't unpleasant. This was something he could handle.
John turning around after fifteen minutes of blissful peace with a hungry gleam in his eyes was not something he could handle.
John just kept on staring, and Sherlock was sure his features revealed his immense displeasure, but either John ignored them or they didn't betray his inner terror, because John kept on staring, kept on inching forward, until he'd begun to kiss Sherlock.
Sherlock knew he should move, should respond, should do anything but freeze beneath John's affections, but he couldn't move, couldn't push him away, couldn't pull him closer. All he could register was a deep displeasure with the turn of events, with the metamorphosis of their relationship. What it meant to enter into a romantic relationship, and with a man like John Watson no less, hadn't truly sunk in until now, until it felt like he'd gone to sleep a man and woken a bug instead of feeling like he'd helped in the slow altering of John's expectations and his own inabilities.
His skin crawled, and he barely suppressed a violent, full-body shudder. Now, it was a choice between his own comfort and John's happiness, and still he remained frozen, unable to process anything but the animalistic realization that his doctor had, perhaps ignorantly, been backing him into a corner, and now his back was colliding with the wall.
He didn't have time to make a decision, though, because John registered Sherlock's unwillingness and stopped.
"You don't want this," John said as he untangled himself from Sherlock's arms. "You never did, did you?"
Sherlock blinked up at John, words jumbled and empty in his mind. He didn't know what to say. There was no clear-cut answer, no certainty to anything but the horrifying realization that no matter how much he still cared for John, even in that damning weak, possibly romantic, sense, he couldn't handle actually acting on anything.
"You didn't do this to placate me, did you?" John asked, that small smile stretching his face into a grotesque parody of his true emotions. "Tell me this wasn't just to..."
"I can't, John...this isn't...wasn't..."
John's eyebrows rose. "Past tense? So, should I assume that you just broke us up?"
The small part of his being that existed unperturbed through the whole spectrum of their relationship begged him to make things right, to fix whatever he broke. The larger part of his being, the part that screamed in revulsion when John's hands wandered and his lips pressed coaxingly against Sherlock's, replayed his revulsion over and over and over until nothing but certainty lingered in him.
"John, I am not fit for anything beyond friendship with you. I told you once that I was married to my work, and I meant it."
That repulsive, painful grin graced John's lips again. "You knew this, and you still chose to lie to me?"
"John—"
"No. You knew. You knew how I felt, and you knew how you felt, and you still acted like we could be something?"
"I wanted to know whether—"
John's eyes darkened, his hands clenched so tightly his knuckles were painfully white. Sherlock's voice fell like a bird shot down by a hunter. "This was an experiment?"
No. Yes. Maybe. Sherlock didn't know, didn't understand why, didn't understand much beyond the fact that he was losing John. Not fifteen minutes ago, his doctor was relaxed in his arms; now, he was tense, ready to strike, anger and hurt draped over his skin like a coat. He could see the dwindling numbers, the clock ticking down down down to the end of their relationship, to the end of everything.
It was so fleeting, their time together. So short, so small, so simple, so subtle, so sublime. Sherlock felt himself examining it as John continued to stand tall, bracing himself for another attack. All Sherlock could do, though, was rewind the tape and press play, watch as he felt himself melt away into something unrecognizable.
He couldn't remember when he'd fallen for John, nor could he remember when he stopped.
All he felt was a panic, a burning need to gather the remnants of himself and rebuild his walls. He couldn't continue existing like this, like some imitation, some beaten dog.
The two men stared at each other for hours before John quietly began gathering his important possessions. It took two hours, two hours of silent shuffling, with Sherlock re-positioning himself on the couch, lying down with his hands hovering near his mouth.
He didn't see John leave, didn't sense the change in atmosphere until the door slammed shut, and all of the warmth in the flat disappeared.
Sherlock sighed and waited for Lestrade's inevitable call for assistance.
Mrs. Hudson noticed the absence in a day. Fighting back tears, she scuttled into her apartment, leaned against her kitchen counter, and braced herself for solitude once more.
Lestrade noticed a week later, when he was in Sherlock's flat. John's cane rested beside Sherlock's couch, John's chair was moved (upstairs, he'd found, where remnants of the army doctor lingered like ancient relics of a golden age), and a bottle of the cologne John always wore sat on Sherlock's nightstand.
Sherlock Holmes rebuilt himself in silence and solitude, a harsher, colder, mimicry of his original, Johnless form. No one told him that it was just a crude re-imagining of the army doctor.
Mycroft Holmes found the army doctor's gun a year later, but by then, it was too late.