Disclaimer: I don't own Sherlock, all rights go to Sir Arthur Conan Doyle, Mark Gatiss and Steven Moffat.
They don't really know when things changed, all they know is that they had. It wasn't drastic, it wasn't ending in them not being friends anymore. It had just changed.
Sherlock had changed more than anything, he was more open, more sentimental. Quite frankly, that was frightening at first. It wasn't a bad change, far from it, but it was, without a doubt, a weird one. Even with all these changes, hands down the most shocking change was that Sherlock was in love. That's right, in love. John can still remember the day it happened.
John was typing away on his laptop leisurely. A case had just been solved and he wanted to write about it as soon as possible so he wouldn't miss the details. This case was very complicated and full of different intricacies that he just couldn't afford to miss. Sherlock had gone out, he's not quite sure where since he didn't tell him, it was strange to think about since Sherlock hardly ever just "goes out" this thought brought John's typing to a stop. The suspicious aspect of that scenario just hit him hard in the face. Sherlock doesn't just "go out" without a distinct reason such as, more often than not, a case. He decided to check his phone for any texts, there may have been a case and Sherlock just hasn't needed his help. No texts. John settled on it being a case that didn't involve his amateur intellect and began typing again.
He can't recall how long it was after that when the door opened and footsteps sounded up the stairs. All he knows is, he finished his blog entry. As suspected, Sherlock walked through the door. What was unexpected was the beaming smile on his usually sullen face. It was quite scary, but also endearing to see his flatmate looking so happy. Sherlock takes his beloved coat off and hangs it up before striding over to his chair and sitting down.
"you look very… Happy" John points out simply. Of course, he didn't expect to say this simple statement and not get Sherlock's sarcastic whip back at him.
"Good deduction John, very good, what tipped you off? My smile?" He asks, voice so heavy with sarcasm that John could hear each word thud onto the floor. He decided to ignore that.
"So, what's got your smile marks out to play?" He asked. Sherlock's smile was still intact as he began to explain.
"Just went out for dinner with someone I met on the case." John felt like he had just been slapped in the face. Twice. First one, Sherlock went out to EAT, and second, he went to eat WITH SOMEBODY. That was just wrong. John had never once seen Sherlock in an actual relationship; Janine doesn't count.
"So, uh… Who's the lucky girl?" He asked. Sherlock's head whipped up to look at him, curly locks bouncing with the movement.
"Do you seriously think I went out with a woman, John? I thought I'd dropped enough hints." He replied. John's mouth fell agape. He hadn't picked up on that at all. Knowing Sherlock, his hints were of an extravagant form, like carving it into a tree on a case, or shooting the wall to form a word. Sherlock never did things the casual way.
"Okay then… Who's the lucky man?" He asked again, changing the gender. Sherlock takes in a breath before relaying information.
"His name is Wesley… Wesley Lizowski. He is a very good pianist." A pianist? John could play piano, he could play "Twinkle, Twinkle" with ease. Why was he examining his own piano skills? He wasn't jealous. Absolutely not.
"So, was it a date?" He inquired, eyes downcast, looking at his cup of tea before lifting it to his lips. Sherlock shifted in his seat, mischief glinting in his blue orbs.
"You're jealous" he states. John was taken by surprise with that comment, showing it through choking on his sip of tea. Sherlock smirked and leaned back in his chair looking pleased, crossing one leg over the other and rubbing at his bottom lip with his middle finger. He knew. There was no point in lying, it would be as effective as reading with your eyes shut. Even though he knows the probability of Sherlock believing him is 0/10, he still gives it a go.
"I'm not jealous, just curious. For as long as I've lived here, I have never seen you go on a date." As expected, Sherlock saw right through it, raising an eyebrow at the ex-soldier. John played innocent though, looking back at his tea before taking a successful sip. Sherlock must have seen no point in trying to prod the doctor to admit the truth, instead he whipped out his phone and checked for texts. A small smile adorned his face at a certain name that appeared on his screen. John glanced up, catching the smile before diverting his gaze back to his beverage.
"Is it a case?" John asked curiously. Sherlock quickly typed back a response whilst answering John's question.
"No, it's just Wes" they've already exchanged numbers? John couldn't describe this overwhelming feeling in his stomach. It was like a boulder was hanging from a string in his chest and suddenly it crashed to his stomach. A very powerful and sickening feeling. Maybe Sherlock was right. When wasn't he right? John shook his head, refusing to believe that he had been possessed by the green eyed monster over Sherlock being with this man. John nodded, trying to seem nonchalant.
"I see…" Sherlock looks up at John, reading his gestures like an open book.
"You have questions" he states. John glances up, locking eyes with his flatmate. Yes, he did have questions, but asking them may make him seem a bit weird. For example, are they together? If so have they kissed? Is he tall? Is he better looking than himself? And so on. Of course, he didn't ask any of these questions.
"What is he like?" John inquired. That question sounds far less intrusive and, hopefully, keeps jealousy off the plate. Sherlock gave John a skeptical look, not believing that was the exact question he wanted to ask. Nevertheless, he answered it.
"He's very nice, smart too. He's also quite chivalrous and attractive. Anything else you want to know?" John could feel the pressure in his stomach getting worse. He shook his head, signalling that he had no more questions to ask the curly-haired man. Sherlock could tell that John was going to keep the rest of the questions locked up and out of reach, so he decided not to pry. One thing he knows about John is if he doesn't want you to know then there's little to no chance that he'll tell you. With a defeated sigh, Sherlock stood up and made his way to the kitchen.
"When you decide to ask the rest of the questions, I'll be working on an experiment." John rolled his eyes 'what else is knew?' He thought before getting up and heading to his room to get ready for work.