This has happened to me in the past except it was with another boy. I'll share my story.
We met on an internet forum which was dedicated to a certain series. He introduced himself as a girl and was the only 'girl' who happened to be active on that forum. I didn't really pay attention to this girl until one day out of the blue she PM'd me asking for my MSN address. Back then I was naive and would give my address if asked so I gave it to her and we started to get to know each other.
I wasn't attracted to her in anyway romantically but when he came out and told me he was a guy I kind of started to develop feelings for him. We shared a lot and talked quite a lot too. He also joked about being bisexual and sometimes he would joke about wanting to suck me off if he could. I thought I was straight at the time so I just laughed and tried to keep my cool. Despite the fact he was actually a guy I felt some sort of strange attraction to him and would get rather frustrated when he wouldn't talk to me becuase he wanted to play games. I understand it's his free time and not mine but he's been spending too much time with games and we never talk any more.
He also managed to get a girlfriend despite the fact how he's 'a weeaboo loser' and now that I look back on the situation I think he only contacted me because I'm Japanese-Australian I don't know why I didn't realise that when he would joke about wanting asians as friends (because all asians look alike?).
When I found out that he had a girlfriend I was pretty jealous but I saw him as a friend although I don't know how he felt about me; so I congratulated him about it because he said it was really hard to get out of his weeaboo phase. He broke up with his girlfirned a few weeks later and went back to gaming.
I was never the jealous type but I was kind of ticked off by the fact he'd rather play games then talk to me. I felt it was unhealthy and tried to break it off I've been going through a tsundere act with him. Telling him how much I hate him, which I do, but I also like him quite a bit.
I've completely cut contact from this boy but I really want to talk to him again. He was the only person I've ever really considered a friend and I'm currently looking for a new one and it doesn't feel good to be alone.
Sorry to hi-jack your topic. I thought you might be able to comfort yourself by knowing that you aren't alone in these kinds of friendships.