Sherlock opened and closed his mouth several times before managing to stutter: "Like a romantic date? With candles and wine and..." he lost his train of thought there, realising with a hollow feeling that he didn't know what dates were like because he'd never been on one.
"Yeah," Y/N answered, her brow furrowing in a way that suggested she was a bit miffed. "Why do you seem so surprised?"
'Surprised?' No, 'surprised' was the wrong word. 'Devastated', 'distraught', and 'shook' came to mind, but they weren't strong enough either. They didn't fully capture the stabbing sensation Sherlock felt at the mental image of Y/N clasping the hand of another man, kissing him and---
He didn't let himself get any further down that road. "I'm not surprised. It's just..." He wanted to say: 'You're mine' but bit it back, cursing at himself for being so possessive, so jealous and petty. He didn't mind loving her and her not loving him back, so much. But her not loving him back and dating someone else? Having to watch her do that, kiss him good night when he walks her home, invite him up to her room, eventually move out, the idea was torture. "All the time you've lived with me you haven't gone on a... date." The word was sour on his tongue.
Y/N shrugged her shoulders nonchalantly. "Well, I feel settled in now, you know? I'm settled into our apartment, settled into my new job, settled into my new life. Tom kept asking me to go for a meal with him and I kept putting him off, but now I think I'm ready to get out there."
"Tom?" Why did he know that name? "Tom as in Tom?"
"Yeah. Don't sound so appalled, he'd be a great partner."
Sherlock huffed as if he thought the exact opposite, but really he completely agreed, and that was why he was appalled. He'd met Tom only once, when Sherlock had dropped the lunch Y/N had forgotten to take off at her work. He'd found Y/N chatting to a tall brunette (Sherlock would be lying if he said he hadn't self-consciously tried to stand up a little straighter when he stood next to him), his perfectly tailored suit complimenting his athletic build, blue eyes bright and genial. Y/N had introduced them, which Sherlock hoped he'd looked convincingly pleased about, and he'd grown even less pleased as their conversation went on. Tom was open and compassionate and romantic and the sort of person who always asks how your weekend was.
Almost the exact opposite of Sherlock.
Tom was perfect.
"Why get back out there with... Tom, though?" He wouldn't mind so much if it was Gary---that five-foot-nine guy she chatted with at break, or Michael---the one with a terrible lisp and bad hair, but Tom? His heart did a painful little twist. Tom would be forever. Tom would make her breakfast every single morning, Tom would send her flowers when it wasn't even valentines day, Tom would ask her to marry him and they'd keep photos of it on the fridge they'd own in their cosy three-bedroom house among finger paintings by their two children--- "I mean, he's okay, but, Tom? Really?" Sherlock wished he would just shut up, but his mouth didn't seem to be a part of him that he could control right now. He hated how he was acting, here was his best friend telling him intimate details about her life, probably looking for support, and all his jealousy-riddled brain made him do in response was question her choices. He should want her to be with Tom. She deserves a Tom.
"Yes, really. I don't know what you mean, he's nice, he's friendly, he's attractive---"
Sherlock wanted to take the blunt little cake knife he'd eaten his brownie with and stab himself violently in the chest.
"---we have only exchanged small talk, to be honest, but I'd really like to get to know him more."
Sherlock made a whimpering noise at all the ways she'd get to know him, but hid it by hurriedly clearing his throat. "Yeah, but... Tom."
Y/N was frowning, now, her lips (that Sherlock had only moments ago daydreamed about kissing) set in a firm line. She crossed her arms over her chest defensively, as if hugging her life choices to her body, keeping them safe out of harm's way. Not that she looked vulnerable, she looked angry and a little bit upset. "Come on, then, what's wrong with him?"
"Nothings wrong with him---"
"Exactly. See, I think you'd pick at any guy I go out with because you think dating is beneath you. Well, it's not, Sherlock, it's not beneath anyone. Just because you choose to never have sex, never love someone, that doesn't mean we all have to, that doesn't make you better than everyone else."
Feeling like he'd just received a hefty blow to the stomach, Sherlock gaped at the woman across from him, for once genuinely lost for words. Of course, she was right; he'd find something to complain about no matter who she chose to date---but not for the reason she thinks. He wanted to tell her right then and there that she was wrong, that he actually did want to do those things very much. That he was already doing one of them and---if it was reciprocated---he'd welcome it with open arms. That he daydreams of doing the other one every time he sees her gorgeous smile, every time she stretches and her T-shirt rises up enough to expose her tummy, every time she lays out on the sofa. He wanted to tell her that every night, in bed, he reaches over to feel the starchy sheets of the other side, wishing someone was there with him.
But he couldn't. Knew he shouldn't because Y/N had been repulsed at finding him cuddling her. Because she's going on a date with Tom. Because she might not even like him at all, now.
Sherlock feels like he's suddenly gone through the five stages of grief, all in one five minutes. "No," he muttered meekly, not liking the sensation of her scowling at him one bit. "I don't think dating is beneath anyone."
He'd nearly added 'Apart from you. Everything is beneath you because you transcend everything.'
"I hope you have fun tonight." He's not even lying. He does want her to have fun, he wants her to be happy, even if it's not with him. Because he loves her.
Y/N's expression softened slightly, seeming glad that she'd hit a nerve, but her mood remained sullen. "You didn't deny that you'd hate anyone I chose to go out with."
Sherlock pretended to suddenly be very interested in a scratch on the table.
...
The walk back to 221B was spent in silence. Sherlock hated every second of it. He hated the fact that he'd made Y/N upset, he hated the fact that he made it seem like he didn't support her, he hated the fact that he appeared to not want her to be happy, he hated the fact that all of this was happening at all.
All he had had to do, he ranted at himself in his head, was say: 'That's nice, I hope you have a good time, will you want dinner or are you eating there?'. That's it. Then hide in his room later today and practice getting used to the fact that Y/N was never going to be with him, so she might as well be with someone else. But he hadn't, he'd argued like an idiot, and now she saw him as an idiot, illogical and irrational, and she didn't even know that it was her that was making him this way.
Sherlock had never been jealous over a woman before. He'd never been interested in a woman before, to be honest. Maybe because other people have always been slightly alien to him. They felt distant, out of reach; women had never paid that much attention to him, no one paid much attention to him, so he didn't pay attention to them. Until Y/N.
She'd come into his life like the sun after a storm, all curious eyes and radiant smiles and infectious laughs, how could he not be interested in her?
...
Seeing Y/N in the dress she'd chosen to wear for her date with Tom caused Sherlock a wave of emotional turmoil that he hopes he will never have to face ever again.
The fabric was thin and looked soft to touch, gently clinging to her figure and highlighting all the right places; her neck that he'd daydreamed of kissing God knows how many times, her legs that he couldn't look at without feeling light-headed, and her shoulders that he'd, well, also daydreamed about kissing (what he was sure was) too often to be healthy. Her hair was freshly washed and styled; all of her was styled, but not too much to stop her looking like Y/N. She was still very much Y/N, and that's what caused goosebumps to prickle every centimeter of Sherlock's skin when she came into the living room.
Sherlock had been reading a book. He'd found that reading books was actually a rather efficient way of distracting the mind when you can't stop thinking about someone (unless that book happened to have romance in it. Then every time a character was mentioned 'caressing his thigh' or 'taking her in his arms' he couldn't help imagine that the couple was him and Y/N).
"Right, I'm going now, bye," Y/N had said, still sounding nettled, not that Sherlock noticed.
He'd looked up from his page and his jaw had fallen so far open he may have dislocated it. She was so...beautiful, she was breath-taking, she was staggeringly gorgeous, she was---dressed like that for someone else. "Are you sure?" His body is doing that thing again; that thing where his petty emotions, primal instincts, have taken the wheel and are driving him down streets he'd rather not go.
Y/N was bending over to put on her shoes and Sherlock had to look away because he'd become uncomfortably hot. "Yes, I'm sure. Are you just mad because I won't be here to watch TV with you tonight? Because I know it's Movie Night, we'll just move it to tomorrow, okay?"
Y/N knows he has Asperger's syndrome and thus about his love of routine, his discomfiture with changed plans, and she'd always just accepted them as one of his many Sherlock-isms. She must have assumed that that's why he's upset.
Sherlock, in all honesty, had completely forgotten that Movie Night even existed, but Y/N had just---unintentionally---handed him an excuse for his crappy behaviour and he was going to cling to it like a lifeline. "We can't just move Movie Night," he complained, hoping he seemed convincingly upset about it. Y/N can't leave, she can't slip out of his grasp forever. She'd fall for Tom, he just knew it.
"We'll have to skip it then."
"We can't skip it either. Stay, see Tom another time."
"No, it's all organised now, I'm not cancelling a chance at a relationship just because you want to watch TV."
Sherlock wilted a little, hurt. The film was not the reason he enjoyed Movie Night, sitting next to Y/N on a sofa, sharing a blanket with her, a bowl of popcorn balanced on their laps; that's why he enjoyed Movie Night. The experience obviously didn't mean as much to her as it did to him.
Y/N finished putting on her shoes and straightened up, smoothing her dress down self consciously. Sherlock couldn't help hope that she'd turn to him and ask him how she looked, or something, so he could tell her she's beautiful just once before someone else gets to do it instead.
But she didn't, she was unlocking the door.
"Wait, I've thought of something wrong with Tom!" Sherlock tried desperately, his insides knotting suddenly and violently, him actually rising from his chair, his book falling discarded to the floor with a papery thud that no one noticed. "He's too tall! Taller men have a higher risk of cancer---"
Y/N rolled her eyes at him, lips twitching into a smile at his desperate attempts to make her stay, and left. Walking out the door and---in Sherlock's mind---out of his life. That's what happens, he knew; people start dating and spend less time with their friends, then get married and make couples friends, then have kids and make family friends, and before he'd know it Sherlock would just be part of her old life, her past, a distant memory of before she became truly happy. That's where his mind was at now; having tried to stop thinking about Tom kissing that mole by Y/N's collarbone Sherlock had always wanted to kiss, he'd distracted himself by thinking about what Y/N dating actually meant. It meant he'd probably have to rent out the room upstairs again. The thought made him grimace. Maybe he'd just get a new apartment, one small enough to let by himself.