>>76214413Firstly because sexual desires are motivated instinct to mate and women playing with each other can't lead to pregnancy. Therefore men don't have an evolutionary reason to object to two women making love, whereas if a another man is making love to a woman you fancy then that's bad because he can get her pregnant, which you want to avoid since you want to be the one to impregnate her instead of the other guy.
Secondly there might be some ancestral blood memory component that makes woman on woman action appealing to men harkening back to ancient lords, kings and tribal chiefs who amused themselves by having their concubines pleasure each other.
