That was the day that Jim Moriarty and his family moved from Ireland to London. He lived next door to Sherlock Holmes, who he soon found out was the resident genius. One day, Jim decided to test it and found that Sherlock truly was as brilliant as they said. So from that day on, the pair were inseparable.
Jim was playing with Sherlock in the Holmes's backyard. They were playing pirates with Redbeard when it happened. Jim leaned over and kissed Sherlock's cheek. That was what had started this whole thing. Jim had already had a crush on Sherlock, but now he was head over heels, following Sherlock everywhere. But then things started to change between them.
July 19th (the next year)
It was mid-July of the next year when Jim realised something was different. Sure, they still hung out. But as they reached puberty, Sherlock and Jim began to develop differently. The standard things were the same, but there were key difference. Especially in their sex drives. Namely that Sherlock's never developed. The taller boy was calm, cool, and collected. Jim was too, but sometimes he just couldn't help himself. His sex drive went mad when he hit puberty and it took him a few years to learn how to control it, but he eventually figured it out. He also realised that he was demisexual rather than aro-ace. Simply put, he wasn't devoid of sexual attachment, but there had to be a bond there first. Unfortunately, as time went on, he realised that Sherlock didn't see him that way. They were friends, sometimes they kissed. There was a sort of relationship going on, but nothing sexual. At first, Jim had been okay with that. But once his sex drive kicked in, it wasn't enough anymore. And while he still loved Sherlock, he needed more.
March 25th (some time in the distant future, when Jim's an adult)
Jim slept around a bit once his sex drive took off, taking partner after partner to sate his sexual appetite. None of them quite lived up to the fantasies he had of Sherlock. But as time went on, he began building up his Empire as well. And while doing so, he was able to handpick the men working for him, which meant he knew everything about them and could choose the perfect men to sleep with. He typically stuck to bodyguards, since they all had a tendency to be tall, rough, and strong, which Jim absolutely loved. And then someone else came into his life. Jim met Sebastian Moran on this day and from then on, they began sleeping together. Occasionally Jim took different partners. But unless the engagement was cancelled, Sebastian would arrive every night, or whenever he was called, and they would sleep together, doing whatever Jim wanted. It sated Sebastian as well, relieving stress for them both until they went to sleep in Jim's bed.
Sebastian and Jim slept together almost every night for years, often doing things others would consider insane. But what Jim didn't know was what happened one night that continued to occur every so often after Jim would go to sleep. Sometimes after having sex, after Jim dozed off, Sebastian would lie awake with Jim against his chest in his arms and would just start thinking. Well, less of a thought and more of a feeling. He didn't realise it for a while, but he was falling in love. It was absolutely mad, but he was falling in love with James Moriarty. And what he didn't know was that Jim was still in love with Sherlock Holmes. He could tell the man was obsessed with Holmes, since most of their work was so Jim could "watch him dance". But he didn't know that they had once known one another.
Sure enough, Jim eventually began to fall for Sebastian as well. The two men fell in love, though neither was brave enough to voice this. Instead, they showed it. Little acts, like making tea or cooking for each other, cleaning up after each other or patching up wounds from work. And the sex, though still passionate, became more tender when either of them needed it. It was nice and Jim enjoyed it. But he was convinced that he would get nothing more from Sherlock or Sebastian. Sherlock was his childhood interest. They were friends and nothing more. Technically not even that anymore. Sebastian was his sexual partner. A fuckbuddy, really. They'd never be more than that, right? Jim was convinced now that he would never have Sherlock or Sebastian romantically. But was that really true? All Jim could do was think and dream, both of which could be dangerous in his mind. But for now, he just settled. Maybe things would be better later. Maybe something would change again. He'd just have to wait.