shouldn't all parties involved be to blame? the single guy sleeping with an attached girl.. both of them should know to stop it becuase neither of them have the right to sleep with each other. the attached guy sleeping around (who WILL get caught) with a load of girls, he's probably (not always) bragging to his conquests that he has a girlfriend but 'he'll make an exception for you, because you're so pretty and i want in your panties' therefore the girls and the boy should know that its morally wrong. but if someone is cheating, they should be respectful enough to come clean, and tell the truth and feel the consequences. i bellieve if an 'affair' becomes very emotional and inter-linked (i.e love), then the other partner in the relationship shouldnt stand in the lovers way, because you never know when you are going to find your life-long partner. does that make sense?