I really have a problem with anyone in a serious relationship flirting. I never really had a problem with flirting until my ex was taking it to far and following up on the flirting. Needless to say that is why he is my ex. My present SO is so the oppisite, or at least seems to be if I mention that I thought some chick was checking him out he really seems oblivious. I think it's the greatest respect I have ever been given.