Why Can't I get over my Ex-Fiance and it's been 6 months?

I was together with my ex for 2 1/2 years. We were deeply in love but than the relationship became kind of boring and it felt like we were going through the motions. In the relationship I paid for everything and resented for that. She wanted to be taken care of and I didn't want to apart of that. I think relationships should be as a close to 50/50 as possible. She was the girl that would walk into a room and all the guys would stare at her because she is gorgoues. She was arm candy but I loved her for other reasons. She had some issues and always wanted to argue which I don't miss at all. Long story short we broke up and a week later she was seeing someone. We broke up because she said "she wants to make sure I'm the right guy for her" I'm not an idiot and knew something was up. After that she got pregnant and was married 3 months later. My problem is that I can't get her out of my mind. I have dreams about her all the time. About 3 months after the break-up I met my current girlfriend and things are nice but I don't have the same intensity that I had with my ex. My new girlfriend has a lot going for herself and she's very pretty but I'm waiting for that feeling to hit. The problem is my ex gets in my head and puts me in a miserable mood. I wish I could just block the dreams and thoughts and move on.. I never got closure from the ex and we havent spoke since the break-up. My dreams are basically dreams about me telling her how terrible of a person she is... Once we broke up it was over. I'm not the pathetic type and I never called her or texted. Im confused wheand want this feeling to leave because I would love to move on and not have these thoughts. . I want things to progress with my new girlfriend because she's awesome and I can see a future with her. Any thoughts?