I'm very close to my brother, and also his ex wife. She's still a member of the family as far as we're all concerned. She's a wonderful human being and that's all I care about.
When they divorced I was devastated and told my brother that it would not affect my relationship with her. He replied that he would not have it any other way. I know this has been helpful to my 2 nephews as well.
It doesn't always have to be ugly!