My husband cheated. How do I let go of the hatred?

My story is a little more complicated than just cheating. We were married for 8 yrs. I found out after he left that the cheating had been going on for most of those years off and on. The only reason why he told me of the despicable things he had done was to piss me off further. I now know there was a reason behind each one of his actions. He is a manipulator and narcissist. He even formed a closer relationship with our daughter when she was 7 in order to take me to court for shared custody. Of course, he blames me for the hurtful things he has done. I found out I was pregnant when he left. We both moved out of the house we are now selling. I moved into a tiny apartment and borrow my mom's bed. He insisted on a 50/50 visitation schedule for my daughter before we went to court. There are so many things I would do different. For one, I would have hired a better lawyer. When I tried to go see her, he would not let me in unless his girlfriend was there who he was cheating with and is now engaged to. They have been together for at least 2 years that I am aware of. He told me a few times that he is a happier person now and a changed person. So, he is basically in love now, supposedly more responsible with the children, quit drinking and is more of a family man. He has decieved me and manipulated me in such a way that I did blame myself for a while. After I had the baby and got rid of those nasty hormones, (yes I blame the hormones) I started to get wiser. Although, I am still beating myself up for trusting him for so long, putting up with his drinking and crap, and especially staying with him until he left ME! He humiliated me in front of family and friends by making everyone think that this new woman in his life is a much better person and will be a better wife than I was. I know my ego is suffering here but how do I get over the anger and bitterness? I know they are not my concern and I feel a tremendous weight lifted since I am not with him...by worrying about his infidelity. But, now but I have to listen to my daughter also tell me how wonderful his girlfriend is. Now he wants me to meet his girlfriend to show me what a great person she is. That just sounds weird to me only because he does not do anything for the good of anyone but himself. She may be, and I hope so for the sake of my kids. He is ordered to keep our 6 month old baby a couple of nights overnight every other week and he has never been an attentive, nurturing guy. I'm afraid he will do what he wants and will not listen to anyone about her needs. I just want to fast forward to when karma catches up to him.