Feeling Heartbroken

This is a bit of a long story so grab yourself some popcorn. I'm bisexual, dating a girl (whom I'm very much in love with) and in love with this boy I've known since 2nd grade, the girl I've known since 5th.

I pined after the guy for 5 years before deciding I was done with men. I realized I was in love with my girlfriend, and we started dating in 7th grade. It's 9th grade now, and I'll be going into 10th in September. We'll have been together for 3 years.

I'm still in love with the guy. We've never been single and ready to date at the same time. I'm in love with both of them, but the girl sometimes can't give me everything I need, and I know the guy could.

The catch is, he has a girlfriend. They've been going out for a few months, not too long. I'm choosing a school to go to next year and, my choices are her school or his.

I know most of the people at both schools, the only real differences are which of them I'll see everyday.

What do I do? If me and her break up, seeing her everyday will just break my heart more, and seeing him and his girlfriend happy together makes me sad.

I need serious advice.