I agree with SexCupid. he can't understand your Non-Male tendencies toward jealousy and need to dominate. Our culture puts so much demand on owning things he can't get passed you not owning her. Put yourself in his shoes. He gets to have your wife and you do nothing completely ridiculous in the standard sociological American view. He wouldn't do it (Although if his wife is that laid back about it he might be doing it and not know.) I say wait till there in the hotel room and in the middle of bumping pelvises and walk in on them. Of course set it up with your Wife first. Then maybe he will get the Idea. On the plus side speaking from experience it can lead to really awesome sex.
