She ignored me, than missed me and now is ignoring me again?

Me and my ex GF broke up 3 months ago over some very minor reasons. She ignored me after that until a few weeks ago. We ended up getting dinner and talking which went great. Than later that night(at 3am) she called me because her current BF locked her out of the house and she said she could go to her parents but she'd rather see me. So I let her stay at my house where she told me that she missed me and was only with him because he allowed her to not think about me. The next day she told me that she wanted a few days to think about what she really wanted and that she would get ahold of me. Then her BF found out about dinner and her staying at my house. They patched things up and now she is ignoring me, probably because I woudln't lie for her when people asked me about it which is how he found out.

Now I am NOT waiting for her at all, I am trying to move on but im still curious what is going through her head. We were together for 2 years and we had a very loving relationship so I know that she isn't "purposely" playing with me. I really believe that she doesn't know what she wants. With me she had the safe, trusting and loving relationship that was going somewhere (I was going to propose soon) and with him she has "fun" because they go out 4-5 nights a week. She even told me that is the only reason she is with him, because he's fun.

She's 25 and I'm 29.