I have a tremendous amount of hostility toward my mother because of my father's abuse?

It sounds like she knows she was wrong. People have their reasons for doing the things they do such as staying with an abuser. It definitely wasn't easier on her. You never know what she went through as a child. Why did she feel like that is what she deserved? You have to ask yourself that. My stepmom was the abuser in my house growing up. I still have a lot of anger towards her and the way she treated us, but I did learn something from her. I learned I have to take it for what its worth. She is a profoundly messed up person. I learned there are people I want to be like and people I don't want to be like. I don't want to be like her. I also learned you reap what you sow. She is 57 years old and has nobody. She and my dad are divorced. None of her children want anything to do with her. She is alone and she earned it fair and square. It does nothing for you to hold on to the bad feelings, but they don't go away over night. Don't let the bad things somebody did to you then control you now.