I really want to be with my best friend but she took her ex boyfriend back?

This girl and I have been best friends for a while, but we have recently expressed how we wanted to be together. She recently broke up with her ex boyfriend who she loved who cheated on her with a girl she hates, and we started to talk. It was a time we used to talk every day on the phone and used to see each other. We would even go to sleep on the phone together. I have always been there for her when she talked about how much she loved her ex and how much he had hurt her(even though I didn't want to hear it), I have been there for her when she cried over stuff, and I even stopped messing with other girls because I really thought I was going to be with her. I love her as a friend right now, but she is the type of what I want in a girlfriend. We made out a few times and we told each other how we felt and we loved each other. All of a sudden her ex boyfriend comes back and they went back out. Not only that, but it be days she don't even text me or call, and when she do call it we only talk on the phone for 10-20 minutes. She be talking to me rudely and cussing me out and really have been changing. I already accepted that we are not going to be together but I still have feelings for her, and it is hard to be friends with her knowing that she got back with somebody who did her wrong and that I could have treated her way better than how her boyfriend treated her. I really have been thinking about not talking to her for a while until I get over my feelings for her, but I don't think that is a great idea. IMO I think I deserve better than how I have been treated by her. But I am asking should I leave her alone until I can get over my feelings for her, or keep talking to her because she is really a good best friend? And I wanted to ask do y'all think she was so hurt over her ex that she needed someone to talk to and she just fell for me? Basically was I just A rebound?