Wife fucking other men.
I have been a cuckold through three marriages, and in the first two, and the first part of the third marriage, I did not fuck any other women. it was my wives who were fuckiing with other guys.
That only changed when I met a guy who wanted to fuck my wife and I brought him home and watched. He invited me to visit him when I was in his area, which I did, and he invited me to fuck his wife, which I did. She was one great pussy, but still I would not have fucked her if it had not been that my new friend needed the same thrill that I did, of watching another guy fuck his wife.
I still wouldn't be able to just go out and fuck some other guy's wife, no matter how hot she was. I need to be the one providing pussy for other men. And the fact that that "Pussy" wears my ring makes it even better.