Do you agree about your husband/ wife being friends with their exes?

My husband is still friends with his two ex wives. It does not bother me at all, afterall he had children by them. I have met both of them and we do get along well with each other. One of them lives in florida, so we do not see her much. The other one lives in our state and we see her often at different functions which involves my husband's son by her. She calls the house at times, and again, I do not have a problem with it.