It’s okay to admit it. It doesn’t make you a bad person if you don’t like how close your partner is to their ex.
It makes you normal. Very normal.
Of course you’re uncomfortable about how close they are. Of course you feel insecure. They used to be what you and your partner are now. A couple. In love with each other. Intimate on all levels.
Now, before I go any further, it’s important to state that some people do get on far better as platonic friends than romantic partners and would never ever want to resume their past relationship. And if there are kids involved, friendship is surely a good thing, right? After all, the kids have suffered enough pain due to the separation; if their parents are on good terms and behaving in a mature way it makes life easier for them.
What I’m talking about is the sort of closeness between ex-partners that threatens their current relationships. Closeness that takes focus and energy away from the current relationship, so it’s a major distraction. Closeness that erodes the trust, respect and security in the current relationship.