Leopold posted ads in German newspapers of the day, looking for "energetic young men" to befriend and pleasure his wife. It might happen, but it's a lesser answer than all of the above. In England, men would sometimes set up their wives to be seduces by a man, so that the husband could then sue the man in court. Many men told me "My wife is the most beautiful woman in the world to me, I'd rather watch her having sex than some porn actress I don't know. Sometimes, the husbands were very concerned about being seen as heterosexual, but they spent an awful lot of time looking for well-endowed men for their wife. Want to learn more about The Psychology of Human Sexuality? Usually, Savage quotes the "eroticization of fear " hypothesis, that these men so fear their wife's infidelity that they eroticize the fear, in order to reduce the anxiety, managing it by sexuality, until they have turned the fear into a sexual fetish. Some of these men talked about treating the wife as a whore, as a piece of meat, and "taking her down a peg. How often do you come across men who want to watch their wife or girlfriend be with other men sexually? I like Ryan's responses, especially the nonpathological view, but think that this is a very complex behavior, with a lot more reasons behind it. After watching their wife with another man, the husband is prompted biologically to have longer, more vigorous sex, has a shorter refractory period between erections, ejaculates harder, and his ejaculate contains more sperm. The financial part is a piece that can't be ignored, as it has been around for a long time. Ryan and Savage's responses normalized the desire and behavior, suggesting that the husband was heterosexual, and was driven by the biological impetus of sperm competition , and voyeurism. Nearly every couple I interviewed told me that after an episode of the wife having sex with another man, the couple felt like they were "in heat. I am smart enough not to dog her about it. I also speculate that there is a degree of vicarious experience here - by being a part of the experience, the husband gets to vicariously experience what it's like to have that greater sexual capacity, and identifies in a strong manner with his wife and the essence of female sexuality in a way that most men never experience. I saw many men who reported that their wives were highly sexual beings, with a greater sexual capacity, and it simply turned the husbands on and pleased them to be able to see their wives sexually satisfied, at a degree that a single husband couldn't match.