How do I get over our past?

To start things off iv never done somthing like this before but I feel like I have no other option. I've read alot of post on the Internet about men having problems getting over their wives/girlfriends pasts. Yet none of them really matched my situation. So I figured this was a good place to ask my question. To start off I've been talking tho this girl since probably around 8th grade. We talked everyday for years and were very much in love. However distance had made seeing each other hard and there was a moment of weakness in our relationship that made what was a very small argument. The end of our relationship. After which we still talked for a few months till she found a boyfriend and I stopped talking to her because I had begged and pleated for her not to. But it still happened and I was very angry alot more so then I think I should have been and the feelings of rage haven't gone away. Now fast forward to a year and a half later we started talking again and things were going good she was writing me letters everyday when I went to basic. We talked for several weeks after I returned. However the pain and anger had came between us and I couldn't even bare looking at her anymore because I couldn't understand why I got replaced and she decides after all that time that maybe I am worth it. Long story short I stopped talking to her for a while because I couldn't stand the fact that she lost her virginty to a guy I absolutely dispised with everything in my being. So now a year later and a nother boyfriend later. We have been talking since January and things are amazing and we've been dating again. But my problem is I can't forgive her when ever I lay with her I see is as somone else she is looking at. I have these thought in my head contasntly about her and her ex's because I had for some reason thought that asking question would be a good way of getting over it. Deep down I feel it's my fault that I let her go and allowed these things to happen. I've talked to her about these issues and she's always so defensive that its hard to get past this and she says that what's happened in the past she regrets and means nothing now but yet I still punishmyself with these thoughts.

Does anyone have advice on how to get over this or at lest to numb it a bit?

Well, how old are you all now?

Basically, I would suggest either counseling or finding someone else to talk to about it to help you deal with your issues. I can understand your feelings of frustration, but if you cannot do much about it, then you have to deal with it by talking about it through a counselor or a trusted friend.