I feel the same. OW has no kids, but H would be at her place, playing with her nephew (who only has a divorced mom, so no dad). And thinking back, he would ask me about questions about kids, which now I guess it was for the nephew. He told me how he would play with the kid at their house and he felt sorry for the kid. I felt sick that he is spending time with someone's kid but neglect his own. OTOH, I guess it's good for him to see what a life it is for the kid to be without a father. I feel the worst for the kid. I read a book about kids in divorced family. One of the worst thing is for the parent bring another partner in the house. The kids never know if this person will stay and become a parent, or if the new R goes sour, the person will be out again and they have to start over with another new person.