Most Helpful Guy
My ex-gf stayed in contact with some of the people she hooked up with before me. This didn't bother me because after all, it was before me. And she hardly (if ever) talked to them anyway. The only one that was an issue for me was that she was still in contact with a guy she messed around with while she was with me. He was friends of her friends. My ex was the real chill type of girl that could easily talk to someone she was with before with no awkwardness on her part. However despite this, I was obviously not a fan of this guy and wasn't very comfortable with him.
So, you can do whatever you want because at the moment (and for your past), you don't have to answer to anyone- even a boyfriend. HOWEVER, you should realize what this contact with ex's might have on a boyfriend you might have. I'm not saying ditch everyone that makes him even slightly uncomfortable, but I think it's important that you can see things from his point of view as well. Like my example above- some people might be an issue, some might not, but all need to be decided on by you. Just understand the implications with whatever you do.