Well, my wife had sex with another man in a wife swap. It was not a fantasy of mine, just a curiosity and a way for my once virgin bride to experience sex with another man. I knew from past experience that sometimes former virgins become very curious about what sex is like with someone else. I would too if I only had sex with one person. What if it was twice as good as what I had?
So we tried the swap with our best friends and we both hated it. My wife was expecting love making which is what we did but instead she got pounded into a couch cushion for 15 minutes and ended up with bruised breasts and thighs. After that she said I am more than enough for her and no more sex with other guys. For the last 44 years she has refused to have sex with other guys even though we were not monogamous at the time.
As I watched my wife with another man I was neither aroused or jealous. It was just interesting to see her have sex form a different perspective. Plus it was just sex and no passion or tenderness at all, so no reason to feel jealous. Watching your wife with another man or having her do it and come home to tell you all about it is a big fantasy these days and husbands watch it in porn and get aroused but in real life their emotions that were not in their fantasy will come out. Plus it will not go according to the script in their minds. Once that genie is out of the bottle there is no putting it back. The wife may feel that she broker her personal or religious moral code or the husband cannot get the image of his wife enjoying sex with another man more than with him. It is all fun and games in your head.
True story. My wife's longtime girlfriend's husband wanted to watch his wife have sex with me. She was already having sex with me and my wife long before he married her, so I said OK. He was fine with me making out with his wife but as soon as I started to undress her he freaked out and she had to drive him home and calm him down. Surprisingly she still kept seeing us as usual. If your husband is truly submissive it can be a way to dominate him while having a little fun for yourself. Some wives are thrilled to be allowed to have sex with other guys, but most are not. My wife does not want sex with other men. As she said, her orgasms are so strong that they hurt at times and cramp up her muscles and if sex was better than that, she could not handle it.
All of our friends who did stuff like this divorced because of it. We were the lucky ones only because we kept sex among the three of us. Try to find an old couple like us who engaged in this behavior on a regular basis. They are as rare as hen's teeth. In fact, the guy who wanted to watch was in a relationship where his wife dated other men and she divorced him for one. The guy gets aroused by knowing his wife is having sex with others. I would not be able to do what he does but it gets him off and they are still married over 25 years so it works for them.