I am also friendly and civil. I see her when it's kid related stuff only. I also don't hang around and chit chat outside of kids stuff. There is really no reason for me to do so otherwise. I want to invest time in someone who will be a valuable part of my life as a friend, partner etc. She's neither of those and so outside of making things work for the kids, I feel no need to create a friendship. She wanted out, she got it.