I lie awake in the darkness, listening to Sherlock's breathing beside me. He is in the deep, coma-like sleep which often comes upon him at the end of a case, when his body can no longer withstand the limits to which he has been pushing it. I could not wake him if I wanted to, and I find I do not want to. He often cannot rest, cannot shut off his brilliant mind, and when he is at his most desperate for sleep, unable to make himself stop thinking or worrying, it seems he can sleep here. I have begun to find him in my bed at the most unpredictable times, whether I am in it or not. He seems to find some kind of peace here, and I am not going to deny him that, when it is such a rare thing for him.

We are not lovers, unless occasionally sharing a bed makes you so. Perhaps it does. We do not discuss it. I am straight, I tell myself. I have always been straight, and had a fairly vigorous love life until I met Sherlock. He efficiently drove off any interested females in a remarkably short period of time, and I'm still not sure whether it was from simple possessiveness of time he felt I should be spending helping him or a deeper jealousy. At some point, I stopped resenting this and now just accept it as a part of my life.

As for Sherlock, I am still not sure of his proclivities. I know him, I know him better than I know myself sometimes. Every tone of his voice, every line of his body, his rages, his habits, his manias, his obsessions. The way his own mind both elevates and tortures him. I know how he sometimes cannot think through the clamor of his own thoughts, how he punishes his body to bring his mind under control. He denies himself food and sleep and sits for hours in positions which must surely have his muscles screaming in pain. He plays the violin ceaselessly to drown out the noise in his head, and covers himself in nicotine patches. When it gets really bad, he turns to the heroin to find a modicum of calm, of numbness. I have even caught him tracing bloody lines on his own skin with a fingernail, though he does not know I have noticed this.

But there is still so much I do not know about him. His past is largely a mystery; he does not tell and I do not ask. I am sure Mycroft would tell me if I wanted to know, but I feel that would be a betrayal. I do not know if he has ever had lovers or if he is exactly as sexually oblivious as he seems. He has made vague references to relationships gone sour in the past, but I have no idea if these were friendships, flirtations, or more, or whether they were with men or women or both. I do not know how bad the drugs got before he managed to get himself mostly clean, or what else he did while he was on them. I do not know if he is married to his work because that is truly his nature and he desires nothing more, or if it is because he feels incapable or out of his depth pursuing romance, bad experiences making him gun shy.

Most of all I don't know why I think about these things. Or maybe I do. One way or another, we have become all the other has, two halves of a whole. Irene Adler once asserted that we were indeed a couple in so confident a way that I could not bring myself to refute it to her. But what is a couple? We live together, we work together, we eat together. We trust only each other. We have killed for each other and will again. I frustrate him with my slowness and he infuriates me with his arrogance.

Other than sex, what separates us from the most devoted of married couples, besides the fact we probably share even more things than most do? I used to recoil from such thoughts, afraid of what it might mean, not willing to let go of my idea of how I thought my life should be. But the truth is, my life was going nowhere until I met Sherlock. I had no future, not even an imaginary one. He has given me my life back, and a life with him is a good one, even if it makes me question everything I thought I knew about myself and what I wanted. I used loudly protest whenever strangers or acquaintances assumed we were dating or together, as though if that were true I would no longer be John Watson, I would be someone different, someone who does things John Watson doesn't do. But slowly I have given up this habit. There is no point in trying to deny we are more than friends, and even less in trying to explain the nature of what we are, when I'm not always sure myself.

There's no pretending things haven't changed between us over the past few months, particularly since the case at Baskerville. We came as close as we ever have or probably ever will to actually talking about us after that case and the result was mainly to assure Sherlock that I wasn't going anywhere, and that we didn't have to talk about it. But since then we have gotten…closer…in very small ways, mostly of Sherlock's doing. I don't want to push him, especially when I don't even know for sure what it is I want from him, if anything.

He will do something in a seemingly casual way, like collapse on the couch while I am reading there and throw his lanky legs over my lap, or rest an elbow on my shoulder while he leans over my computer to read what I am writing. If I didn't know better, I would say he was just doing these things absently, unaware, but then I catch him studying me with sharp eyes for a reaction, seeing what I will do, trying to figure out if he has crossed a line, as though nervous that I might reject his touch, disgusted. I find myself studying my own reactions as well, almost clinically. How does the ostensibly straight man respond to the touch of a hand? A leg? Another man in his bed? I usually find myself discomfited but pleased. Or perhaps just discomfited that I am pleased.

I can never tell if this is Sherlock's tentative way of trying to inch forward, to move us into uncharted waters, to see how far I will let him take things, or if it is just a desperate need for simple human contact and reassurance from me that he doesn't know how to express otherwise. Perhaps it is both. He certainly seems slightly less manic, less sulky when we are in proximity, and I've noticed he has begun to seek me out when he is especially tormented by something and station himself near me, not talking, not even touching, just somehow seeming to find existence slightly more bearable when I am near him. I don't think he knows he does this, but I find it touching and also a bit sad.

Of course, I am not any better at articulating my needs that he is, even if I am slightly better at understanding the emotions of others. I am frequently embarrassed of my own emotions, and Sherlock's inability to discuss these things is often a relief. But I can't deny I have thoughts and feelings that I wish I didn't. Not so much because I think they are wrong, just because I don't want to deal with them. Sometimes when he is at his most restless, storming about the flat, torturing himself mentally and physically, frustrated with a case or with the intense boredom he can never seem to escape, I get the wildly insane urge to jump him, if only to give him somewhere else to direct his energy, something less destructive and outside of himself.

I am immediately appalled by such thoughts, and then I am appalled that I am nowhere near as appalled as I would have been a year ago. It no longer seems quite so strange as it once did, although I still don't know if I really could cross that line, and I certainly would have no idea what I was doing if I did. I wonder what he would do if I attempted it? Would he look at me coldly with those pale eyes, baffled, saying something like "John, what on earth are you doing? I thought we had an understanding." Or would the walls of isolation and confusion finally come down, releasing thirty-odd years of frustration and hunger and raw need that I suspect is behind them? I am afraid to find out.

I am likewise afraid to find out what I would do if he ever jumped me. I suspect he would not, not suddenly – he seems far too hesitant about us to do such a thing without warning, and I'm still not even sure if that is what he wants out of all this. But when he works himself into a state, he can be rash and impulsive and desperate, and I can imagine one day he might just throw caution to the wind. What would I do then? I honestly don't know. My feelings and desires regarding Sherlock and my own identity are so conflicting and entangled that I can't seem to give myself an answer, and thinking about it is exhausting.

And as much as I worry about the meaning of us, I worry about him far more, in a more fundamental way. I worry that his own intelligence will drive him truly mad one day, that he will go too far into his dark places, hurt himself too much in an attempt to find relief from demons or boredom, that he will cross that line that Moriarty crossed and lose himself entirely. That I will lose him entirely. I am afraid that his addictions will claim him one day and that there will be no bringing him back.

I do what I can to keep him present, to keep him in this world, to engage him with things outside of his own head, but it is difficult. Sometimes it works, and I can distract him with a game or a case or an argument or a laugh. But sometimes he looks at me like he doesn't see me, and I know he's deeply caught up in some problem that he can't or won't explain. Sometimes he disappears for hours, chasing down a criminal on his own or on some other mysterious errand or experiment – those times worry me the most, because there is no one to stop him from risking everything just to have something new, to break the dullness. I fear that need will be the end of him one day.

It is starting to get light out and I realize I have not slept a wink since I woke to find Sherlock next me. Usually I fall back asleep and when I wake again he is gone already, and we go about our day without a mention of sleeping arrangements. He is sprawled on his back now, well over onto my side of the bed, feet hanging off the end slightly. I move to sit up, thinking to let him finish sleeping for as long as he needs to – I know it's been at least three days before this without rest for him. As soon as I move, he stirs and wakes, seeming startled to find me there. He freezes, like he has been caught, as if I had been previously unaware of the occasional existence of another person in my bed.

He blinks, trying to clear the sleep from his mind, and pushes himself part way up on his elbows. "John…" he says awkwardly, "I'm sorry, I didn't realize, I must have gotten turned around when I went to bed last night, I was quite tired…" The excuse is shamefully flimsy and he knows it. I resist the urge to go along with it, to avoid any hint of deeper emotional content.

"Sherlock, it's okay," I say softly. "It's… nice to have you here."

His eyes widen, but he says nothing. His arms are bare, and I can see a network of track marks and faint scars on his inner forearms, as well as larger scars from fighting and pursuing criminals and God knows what else. I give him a little smile, sadly, and touch him lightly on the inner arm, the first time I've initiated any real contact beyond a clap on the shoulder or a rare, manly hug.

"But no more of this," I add, tracing a line that is fresher than the others.

"John, I –" he begins.

"No more." My voice is quietly firm, but not angry. We have argued about his drug use and I have kept silent about this other coping mechanism, but seeing him like this I realize I can't bear it any longer. "Please, Sherlock."

Instead of deflecting the conversation or becoming defensive as I expected, he is still for a moment, then nods. "No more, John."

I feel relief fill me. I do not think he would lie to me, not here and now. I squeeze his arm slightly, in gratitude, and get out of bed. The worry and uncertainty of the night has dissipated into a sense of peace. Maybe this is going somewhere, and maybe that's okay. Or maybe we will remain exactly as we are. I realize I am no longer concerned about it. I understand now that I chose my path a long time ago, and that path is wherever Sherlock Holmes goes. When I moved in with a stranger, when I defied every word of advice to stay away from him, when I killed a man to save him, my course was set then. I will follow it wherever it leads.

Sherlock still looks bewildered at my reaction this morning and has not moved. I give him another smile, less sad this time. "Come on, I'll make us some tea," I say, and head downstairs.