HI i go to a school in wisconsin so you dont get this confused with someone else...

so i go to school with this girl whom sits with me in a class.... She has a boyfriend but she complains about him all the time...I like her alot ive liked her sence we met and idk if i will ever stop.... but my best friend just told me that if she and her bf break up that he is gonna ask her out...what the heck am i supposed to do? im so confused...