A/N: I wrote this in response to a previous reviewer's comment about Watson probably wanting to run off eventually with someone (a woman) who can fulfill both his emotional and sexual needs. Which may be a valid concern to have in OUR world but in my world? That is a non-issue, baby.

Asexual!Sherlock/Straight!John - platonic romance, nonsexual soul mates.

Time jump in this one.

Two Exceptions

They've been living together for five years when John comes home from work one afternoon to find Sherlock standing by his favorite living room window, staring outside, hands in the pockets of his trousers. John immediately knows something's wrong; he can see it in the other man's posture. He lets the strap of his messenger bag slide off his shoulder and sets it down on the floor against the wall. Sherlock hasn't had one of his moods in months. Maybe this is a beginning.

"Sherlock," he says. "What's the matter?"

"I'm thinking."

"I can see that."

Silence. John waits, and after a couple minutes, Sherlock barely glances over his shoulder at him but otherwise remains where he is.

"How long do you intend to stay?" he says.

John says nothing at first, uncertain of what he heard, processing what it means.

"Excuse me?"

Sherlock repeats himself, this time saying the words more pointedly.

"I don't understand the question," John says.

Sherlock gives one of his long-suffering sighs, keeping his back to John because he doesn't know if he would be able to retain composure through this conversation otherwise.

"How long are you going to live here?"

John blinks at him, dumbfounded. "What kind of question is that?"

"A rather practical one, actually. What normally happens when two adults who aren't shagging live together is the arrangement only lasts until one of them develops a relationship with a third party which does involve shagging and, at any given point, decides to move in with said third party. Seeing as how sex isn't exactly my area, I will not be the one to terminate our living arrangement, it has to be you, and therefore, I ask the question: how long do you intend to stay?"

John hates it when he gets like this. "What are you bloody talking about? Did someone say something? I left this morning, you were fine, now eight hours later you've decided there's an issue?"

Then again, John thinks, Sherlock Holmes can think more in eight hours than the average person thinks in two weeks. In all probability, he's been thinking about this issue for days and only now came to enough of a conclusion that he felt ready to bring it up in conversation.

"No one said anything." Sherlock is perfectly calm. Which is scaring John more than it should. "You've been here five years, two months, and eleven days. It's quite a long time. Which means that time must also be approaching its end."

"And why is that? Do you see me dawdling about with a girlfriend on my heels? For God's sake, you know every woman I've ever seen since we met, despite the fact I don't introduce you. Obviously, there's no one serious, you know there isn't. So what's all this rubbish?"

"Are you looking?"

"No!"

"Why not?"

John stares at Sherlock's back, unable to respond. It's not that he lacks an answer—he long ago worked it out in his head why he's lost interest in getting emotionally serious with women—but it would go against his nature, perhaps even against the nature of their relationship, for him to outright admit that being in love with one person as much as he is with Sherlock is enough. He was sure that Sherlock already knew, because Sherlock is the first to know everything ninety-nine percent of the time. There's hardly been any discussion of John's dates before; he thought Sherlock was all right with them. And if Sherlock truly does know everything there is to know about the women John dates (even more than John does, no doubt), then he knows John has no significant emotional attachment to them. This sudden outburst makes absolutely no sense, especially coming from the most logical person John knows.

"Do you want me to stop dating?" he says.

"You're dealings with women have never been a problem before, and they certainly aren't now. Surely you're smart enough to know that isn't what I'm talking about."

"I have no bloody idea what you're talking about. Nothing's actually happened to justify this conversation. You've fabricated it out of thin air. I've been here for five bloody years, dealing with you're absolutely ridiculous arse every single day, don't you think I would've left by now if I wanted to?"

"If you haven't met the woman you're looking for yet, then naturally, staying would be the most sensible thing for you to do. That has no bearing on what your intentions are for the future."

John occasionally has moments in his life where he is filled with the purest, most powerful desire to clock Sherlock square in the face. Or better yet, smother him with a pillow. This would be one of those moments. He has to gather himself before speaking, he can almost feel the frustration seething through his teeth.

"Sherlock. There isn't any woman. And if you're so bloody smart, you should know perfectly well on your own why that is. Now, do me a favor and pull your head out your arse before I come over there and do it for you."

Sherlock bows his head, the slope of his shoulders giving the impression he's in mourning. He continues to speak softly, with resignation in his voice."I watch people for a living, John. I know how they work. You've been an ordinary, heterosexual man your whole life, you're not going to suddenly change upon meeting me, I can't provide you with all the things an ordinary person needs to be-"

"Oy! Shut up! You're absolutely fucking right, I haven't changed. I'm still interested in shagging women. Last time I checked, you're not one of them, so I have no interest in shagging you. But what the hell does shagging have to do with whether or not I live here? And another thing: I don't give a bleedin' shite what people do or how this all normally works. You're sure as hell not most people, and most people aren't living with you, I am. Christ only knows why. What gives you the right to assume you know what I want better than I do? If after all this time, you still think I'm just using you for a stand-in while I wait for someone better to come along, you really are stupid."

Perhaps that came out much harsher than John intended, but he hasn't been this upset in a long time. No, never mind, it came out exactly as he intended. He waits for an answer, but Sherlock doesn't move or speak, just stands there by the window looking forlorn, the utter sod.

"I can't deal with this bollocks right now," John says after a bit. "When you feel like being reasonable again, let me know."

He goes up to his bedroom, slamming the door just to make himself clear.

John makes dinner and gives Sherlock a plate without saying a word. Sherlock takes it, without saying a word. John eats in the kitchen. Sherlock eats on the sofa. They listen to the telly.

John lies awake in his bed for a few hours, trying to sleep but failing, waiting for Sherlock to join him. Instead, at two in the morning, he hears the front door open and close.

Damn it.

It's quarter to three in the morning, it's cold, John has to work in the morning, and where is he? Going after Sherlock bloody Holmes. He thought about going to sleep for twenty minutes before he got dressed and left the flat; if a grown man wants to have a tantrum, let him at it, right? But it didn't take long for John's mind to suggest cocaine, drinking, fights, suicide—oh, God, suicide, confrontations with terrible people, and he was still hopping into his right shoe as the cold air rushed into his face when he let himself out.

Other people might say, how the hell do you expect to find Sherlock Holmes when he could be anywhere in London? But the man's surprisingly simple sometimes, and John knows where to look. He can feel it in his chest, and fuck him, isn't that just the whole of everything between them?

There's a small bridge fifteen minutes by car from Baker Street. John takes a cab, thinking the whole way that Sherlock most certainly walked.

He sees the tall, lone figure right away, clear against the night sky, and when he reaches Sherlock, the plumes of white breath. Gets closer and sees tracks in Sherlock's face, the glassiness of his eyes briefly before Sherlock turns on him, starts to walk away.

"Sherlock! Oy!"

John catches up to him, cheeks already pink from jogging the short distance in the cold. He catches Sherlock by the sleeve of his coat and pulls him to a stop.

"Look at me!" John demands. "Look at me, you fucking idiot!"

And when Sherlock does, his face almost startles John backward. He looks gutted, skin white like a frozen corpse in the river, those eyes chilling bright, tears gone but evidence left.

"Go home, John. I just needed to think. I needed to get out of the flat."

"You need to quit bloody thinking for a month, is what you need to do! Jesus Christ! Stop this! Just stop!"

Sherlock pulls out of John's grasp.

"I can't have another argument right now," Sherlock says, fidgeting on his feet, going in circles. "I can't, all right? Please, go home."

"You're out of your mind if you think I'm listening to you. It's freezing, you've already been standing out here for at least twenty minutes, maybe more, because you're a fucking twit, and it's the middle of the bloody night. We're getting in the cab right now and going back."

Sherlock starts walking away again, but John follows, yanking him around. And when he does, Sherlock gets right up into his face and says, "Just admit you're going to leave. Admit it. Stop dragging me along."

"You are out of your bloody mind," John says. "How many times, in how many ways do I have to tell you I'm not bloody leaving? I'm here because I want to be! Why is that so hard for you to believe?"

"That's not how it works!"

"Fuck how it works! I'm not the ordinary man, I'm fucking John Watson and you're Sherlock Holmes and what we have is the exception to the whole bleedin' rule book! Now, will you shut up and just be happy?" John takes Sherlock's face in both his hands, forces Sherlock to look at him. "You give me everything I need to be happy in this fucking ridiculous life, and the shagging doesn't matter. Stop being so fucking dense for a minute and realize that the people you spend all your time bloody analyzing spend their entire lives looking for what we have, for even half of what we have! Shut up! Just shut up!"

Sherlock looks at him, really looks at him, computes every minute detail about John's face in that moment, the expression in his eyes and mouth and brow. Can he believe John? Can he take that risk? The last five years have been the happiest of Sherlock's life, but it defies logic, normal people don't live this way, how can it possibly last, what are the actual odds of one exception finding another?

John's leather gloves are cool on Sherlock's face, thumbs pressing into his cheeks. Their faces are close enough that they're breathing into each other's breath. Sherlock isn't sure if his heart is too fast or absent altogether.

"You aren't a woman," John says. "But no woman will ever be Sherlock Holmes."

Sherlock doesn't even have a facial response to that. He rests his head down into John's shoulder, and John holds him up on his feet for a long moment. He can feel Sherlock trembling. And he meant every word. Every word. Maybe life with Sherlock isn't normal, maybe it'll get him killed, he shags people he doesn't love and he'll never have children but Jesus, he doesn't care. He just doesn't care. Life with Sherlock is electrifying, addictive, comfortable, an old song he forgot he knew all the words to, life-giving, passionate. This man—this brilliant, crazy, difficult, outrageous man he's holding up—he's never loved anyone the way he loves him. He's never been loved by anyone else the way Sherlock loves him.

John's no fool. You don't throw this away. Not for anything.

In the cab, as they go back to Baker Street, both of them staring out their respective windows, John says,

"What do you think of a civil union?"

Sherlock closes his eyes and smiles.

John reaches out and takes his hand.