When in my early 30's, married, I realized that fetish was exciting for me and the fantasy would make masturbation much more intense, I did not understand how that could be. I had always been very assertive sexually, very possessive. 10 years later, in therapy I discovered it was triggered by very strong abandomnent issues that I have. The fear of losing (being abandonned) my gf/wife to another man and watching them have sex intensified my emotions, my fears. But after my orgasm, if it had been real and happening in front of me, I would have stopped it most likely using violence. For me it's only a fantasy. I love sex with women too much. If ever a woman comes into my life and at one point tells me she needs to have sex with other men, I'll either leave her or tell her to go ahead, but that I won't be at home when she comes back, I'll be somwhere with another woman having great sex!