Issues in the bedroom

My husband and I have been married for almost a year. We have had issues in the bedroom. So we opened our marriage. And although I have a girl and he had a man on the side our sex life isn't better. We still love each other very much and having something outside our marriage hasn't damaged our marriage. I don't enjoy sex with my husband lately. And he can't even come to climax any more. He is seeing a doctor but still. How do I tell him he doesn't satisfy me. He always did before but now it just kinda stinks. I don't want to hurt his feelings but I do want to tell him that I don't enjoy sex with him any more.