No closure? What to do?

I dated his girl in the summer. We hit it off really well and loved the same stuff. We was falling really fast and I wanted to take things slow since we just met. When summer ended, it was back to work for me and college and work for her, so we wasn't around each other that much. I love her so much but I need to take care of my priorities.. She was overly-possessive, when I miss a phone call she'll be mad. I had alot on my plate and I just needed a little space or break. � Overtime, the relationship became a co-dependent one, we became obsessive over each other and it was becoming very unhealthy. My friends were concern and every time I talk to her about this, she'll get very upset and think I'm playing games with her heart. I wasn't even trying to and I didn't wanna lose her so I gave in.. Things only got worst and I was slacking off big time! It was hard because she just wouldn't understand and get angry easily. She got mad and told me to get lost which I did. I got my life back in order and balanced everything. She came back apologizing and saying she wants to try again. So we start off and things were going great until she cheated and dumped me unexpectedly while i eas sick. Ran off acted like I didn't exist or wouldn't talk to me. Why would she do this just to hurt me? Anyways, I began to accept this and move on until she came back saying she miss talking to me and let's be friends. Trying to act like she did nothing wrong and waited too damn long to talk about this. I was about to give in to her but I was just too hurt so I ignored her. I just wanted to know why she did it and she tried to swept it under the rug.So now she's acting like I never existed, talking behind my back, sometimes i feel like she stalk my profile and might be dating this new girl. I'm started to see someone to, but I'm kinda angry that she's acting this way and won't tell me why she did it. I just want closure but I can't.. She just acting like se did bogong wrong and turning the tables on me for no reason. I want to forget about her