My head is such a mess at the moment. It's been spinning for a week now and i still don't know what to do. Help. Please. If you can read through it all. Please.

Been going out with my boyfriend for 2 years now (on 25th March), it's a long distance relationship, since we're at different Universities. We see each other roughly once a month for 3 days or so during term time, and a bit more in the holidays. So it's not really your standard relationship to start with. Add into that, that i'm bi, come from a less than ideal family (so SI and other problems in my past, which occasionally resurface), and hated men before decided to see if he was different (mainly after a prick that took advantage of me 3 months before met my bf, but my father doesn't help matters). My boyfriend comes from as normal a family as i know, and the only 'problem' would say he has is being self-critical sometimes. However, he's been so understanding and supportive of me and helped me through such a lot. Definitely loved him so much, but now not so sure.

Last Sunday, he came to visit me at Uni. Monday we had a fairly big disagreement because of the sport we both do, he beat me, but was getting cross every time i scored, despite the fact that he hasn't trained since Xmas and i have. Tried telling him not to be so hard on himself because he hasn't been training, but he just got more annoyed at me. We drove back to campus in silence and didn't really make up properly. Then Tuesday evening we went to something together, but at the end when everyone was packing up, he went off to a bar on campus with another girl (who i hardly even know, but even he'd just met) without even telling me. My history also came to get me and felt triggered because of something unrelated, and retreated into myself, he got angry at me, and angry at himself because he didn't know why he was angry, but we didn't speak for a good 2 hours. Eventually we did, but again the problems weren't resolved.
He has since apologised, by text and in person, for 'being a prick' those two nights (and given me a new necklace), but it really left me questioning how well suited we really are anymore; we've both changed at uni.

Wednesday night, a girl at uni (who, i'm ashamed to say, i have a crush on - it's always been the way for me though, to like a girl and a guy at the same time) told me she had a crush on me. She's been my friend since Sept, but we had recently been getting closer, and she broke up with her boyfriend of 2.5 years because their relationship was making her unhappy.

Really don't know what to do. Do i stay with my boyfriend and try to work through my doubts? Because we've had a lot of good times together, and he's done so much for me. And in a card he gave me with roses for our anniversary he said how happy being with me makes him. We could still probably have an ok relationship, and one that could last for a long time.
On the other hand though, there's so much doubt in my mind now. Are we really as obvious a couple as we apparently were before we even were together?
Then this girl, she's been a good friend to me too. And i like her, but her ex would be so angry at her (and me) if we got together. Plus i'm all too aware that i could be nothing but rebound to her.

So, how on earth do i work out where to go with my current relationship; and what do i do about this girl?

(sorry for the length of this, it's just the surface of what's been going round my head all week and probably not very well written. thank you for reading it through though )