I want my husband to drop his best friend
Do you hate his best friend because he is taking time away from you?
No, I just hate him because he is an asshole and a cheater, and if my husband remains friends with him I'll have a bad time.
You don't have to like all your partner's friends but you cannot stop him from seeing them. It is wrong and people will think you are controlling.
So cheating and asshole behavior toward everyone, including your friend's wife, is okay, as long as I don't seem controlling? I don't agree.
I'm not saying you have to put up with someone treating you badly, and your husband shouldn't either. I'm just saying you only have a right to control who interacts with you. You could compromise with your husband that, while he has the right to keep his friend if he doesn't see his behavior as problematic, you also have the right to limited contact and strong boundaries with that person.