Wow, so much drama going on here (in a good way). I love it.
First of all, why does the remark about Jimmy at the end there give me an ominous impression? Jimmy suicidal tendencies, and all.
That said, as much as I hope he hasn't done anything daft, he can't expect Billy to live for him and his desires. Billy's just not into him romantically, Jimmy needs to get his shit together and realise that already.
As far as Bobby and Ian are concerned. Is Ian intentionally flirting with Billy, or is he just a 'touchy feel-y person? Some people are and mean nothing by it. Don't even realize they're doing it half the time.
I know we're talking about 15 year olds here, but Bobby needs to quit being so paranoid. I mean what's the point in the relationship if you can't trust your boyfriend? Clearly if he can't trust Ian, then there's more than just Billy being a potential issue.
Communication is really the key here. Bobby needs to talk to Ian. And I also think that if Ian knew that Billy was gay and in a relationship, he'd back off a little. Maybe he's just flirting with the "forbidden fruit" - if he even is flirting with Billy.