need advice: my friend's gf is a slut

ok… heres a senario… your friend. actually many friends that i know do this… date a girl for a while. and cheat on them or make several attempts. you are also very good friends with the girlfriend too…

do you tell the girl friend, that is your good friend also. or do you just let the male friend do his own thing…

like i said its not my business what their relationship is about… (i know this is slightly unrelated to the OP) but i still feel i should stay out of other peoples relationships

edit: I’m not making a joke of your thread… I’m giving an alternative view…