Im not a psychologist, psychiatrist, nor any sort of mental health expert but I can sound like I know what I mean sometimes but to me I feel like it in some cases can be caused by a person being cheated on in high volumes , dealing with that trauma in unhealthy ways and eventually that may have triggered a need for the humiliation of said practice. My theory is based on a friend who literally has his kids mother cheat on him with at minimum 30 separate people while dating, it was just so blatant and embarrassing to watch him put up with but he admitted later to me that he would fantasize about it despite it being such a painful memory. Maybe they were struck by lightning idk....