Wow I can so relate to that. When I left my XH I was talking to my dad and said "how is it that someone can treat me so horribly, and yet I still be bad about leaving them"
I think its just the nature of people that are compassionate, empathetic people.
Really though you are doing him a favor. He will never learn or change if he isn't given consequences of his actions. Everything you are doing now, he had it coming and then some.
And the most important thing is that you are doing this not only for yourself but also your daughter. She now will not be exposed to a bad relationship in which her mother is mistreated.
Just stay strong and don't lose site of his actions over the past years. Try not to feel guilty or bad for standing up for yourself, and enforcing boundaries and leaving an unhealthy abusive relationship (Serial cheating is a form of emotional abuse)