Is it wrong for me to try to tell my boyfriend who to to be friends with?

Its one of his friends, Who is female, Who he has slept with recently but not while we were together, Although he did lie about ever sleeping with her and when I accused him of it, Got horribly upset, Though he did admit recently that he had slept with her. I’ve expressed great concern and I’ve let him know I’m very uncomfortable with this relationship. He’s probably known her around 6 months and I can’t understand why its so hard for him to let the relationship go. She lives in the same building as him and feels she can come knocking on his door when she feels like it. My biggest problem is there is no compromise, He will not let her go, Is this wrong?