Asking Eric: Is it safe to vacation with an ex in the mix?

Dear Eric: My boyfriend and I have been together for six months. We’re men in our 30s. I have a very friendly relationship with my ex-partner that my boyfriend resents. He never has anything nice to say about him and is always misreading the things my ex says and does.

I think my boyfriend mostly resents the fact that I have a close relationship with my ex because his relationship with his ex is basically nonexistent. I don’t blame him for wanting nothing to do with his ex. Everything I’ve heard about the ex sounds terrible.