I used to be bi? am i lesbian now?

I know that i was born bi as girls and boys have always turned me on ever since i was a child. I have a boyfriend who I've been with for a year, and honestly i used to be madly in love with him and he turned me on allll the time but after a few months i realised that he had been lying to me, talking to other girls behind my back and he's stopped turning me on after i found out about eveything.. I used to masturbate over boys all the time now i don't at all. I get butterflies around some guys but thats it. Ive loved about 4 guys, maybe not love but I've had strong feeling for them and they would turn me on. Ive also haf loads of crushes on guys. Girls turn me on a lot but i don't like to think about them.. I have never fell for a girl before and still haven't sometimes i doubt that i will...everything has changed guys don't drive me crazy anymore i keep thinking that I've turned lesbian...is it just a phase ? I want to be with my bf, when i think of him with someone else i cry or get really jealous what is wrong with me?help x