Why? Are women possessions? Sometimes people just enjoy sexual experiences and don't take this stuff so seriously. Not every instance is a "cuck" situation where the guy wants to feel degraded. Sometimes people just have agreements and don't mind fooling around responsibly. A lot of these relationships are very happy and long lasting because of the level of communication that is required. 99% is not even close, since this is generally viewed as taboo it is not openly discussed very often. It goes on much more than you would think. It's not my thing but I can fully understand those who live this way. Mocking and humiliating people is a sign of weakness.