I haven't but my wife has had sex with many men while we have been married. I have watched my wife have sex with about 17 of those men and I still enjoy watching my wife have sex with friends and strangers.
I think about other men having sex with my wife. Normally it involves a group of men, strangers, and they use my wife to satisfy their sexual fantasies, often very dirty fantasies, in public places. My wife is always happy to be used by the strangers in front of me and other people.