ya know,
this is a really great question.
your reputation lies in whether you are a pvssy or a strong minded guy who looks beyond some other idots drunkeness, and lets it pass
if you got into a fight for every time your girl got hit on by a guy, you would be dead
Your girl would hopefully feel bad if you got into a fight, and were seriously injured(if he had many friends)
but does she consider that you might get beat up? for sticking up for her? NO
she is more valueing her position that some guy univitingly complimented her
while she assumes it wasnt a compliment
there is a fine line to draw as a man for this situation, is the guy harassing her? or was he some obnoxious drunk just passing by?
I think you know where to handle it from here, if your girl doesnt understand that guys will make rude remarks, even while with a guy, and choose you pick a fight with him vs letting it go,
your girl needs to be kicked up several notches