Is it normal to want somebody to masturbate to me getting fucked?

I've always been a very sexual person. I've recently (2.5 years ago) given up a very promiscuous lifestyle for one man. Our sex life has always been great but lately I've been having a fantasy that I can't get out of my head. I'm dying to have somebody watch us fuck and get so turned on that they either have to masturbate right then and there, beg to be allowed to join, or have to fuck somebody else while it's going on. It could be a man or a woman, but preferably multiple people of both sexes. Unfortunately, I can't see how this fantasy could ever become a reality.