Is love really a choice?

I have been wanting to date a girl for a long time now but she always chose to get back with her problematic ex boyfriend over and over again and we could never give our thing a chance. I know we love each other but she believes because she has invested so much in that relationship it's hard to completely let it go. We're very similar as people which also makes her think that I don't bring as much to the table as a contrasting person would (her ex).

I really love her and would do everything in my capacity to keep her happy. Idk where am I going wrong.