I kinda did, a guy i met thru work and I, had become pretty close friends. And he was engaged to this girl. And one night at the bar she molested me. and we hooked up for weeks behind his back and she finally broke it off with him and when she did that i said whoa. You blew it im not gonna be with you. you better go get your man back. and he wouldn't take her back. so thats what you get for being a whore.
Me and the guy are obviously no longer friends.
Im a terrible person yada yada i know but ive been cheated on plenty of times it was nice to be on the other end for once.
Also yes stay out of it. unless your really good friends with the guy getting cheated on. Then its your duty to tell him. Thats what my friends always did for me.