I don't know if this is the right section, but I didn't find a more appropriate one.
My husband has 2 exes (one he's known since teenagehood), another was a rebound right after the first and well, both didn't work out. Both women never accepted the separation and maintain a relationship with him (yes, they have kids) that is more close than what's needed for parenting (2 of the 3 are young adults).
Moreover, the young adults don't go to our house (we live 35 min away), so he visits them in the ex's house twice per week. So they all socialise, not only with the ex, but with her new partner as well and continue staying close. He gives them gifts on mother's day and birthday, they send each other messages, ask for small favors, share their trips, etc. It's not every day, so I can't argue that it's too much, but it's there.
Well, it bothers me. I feel excluded. The rare times we are in the same space with any of the ex, they start chatting with my husband like old friends that they are and our young child and that bothers me too. So of course, I've been accused of being posessive, which I admit I am, but it's a feeling that's there and it causes issues. Basically recently I had a fight with the ex, which means that I will no longer be invited to her house.
Soon there will be times when my son will be invited to the ex's house (ex for one of his brother's birthdays) and I know that my husband with my son will be socialising with the exes and their partners while I'll be home and I just can't accept this! How can I let it go?