my exgirlfriend is playing me loke a toy

Hello, my name is Dominique ajd I am a 22 year old male. Ive been dating this girl for 2 years. We had our problems that we tried to solve and we loved each other a lot. We broke up twice and got back together twice but this third time is making me worried and I think it is conclusive. The reason im saying that is because for the last couple of months she turned into a different person and started acting like she doesnt care. All the things she does wrong and I tell her about dont affect her behavior and she does them over and over again and I keep complaining about them and that makes her more angry. Finally she broke up with me saying we should remain friends but with benefits. Means we still kiss each other and have some sexual intercourse. However I knew she was seeing another guy, not anything serious but its driving me crazy. So she said that we should be just friends when I told her how angry I was about it. Today she texted me and asked me out to see some movie. During the movie where some sex scenes passed, she grabbed my hand and started teasing me by sucking my finger. So I thought she was to get somewhere with inside the theatre she even put my hand on her boob. When I came close to kiss her she backed away and never did anything again. I need some help this is making me crazy especially when she talks about that guy and how he met her father that I never met because she said shes not ready to introduce me to him. And she talks about how she likes something he did and made her get attracted to him. What should I do??