But that's the point -- what if there is no man in the situation? What if a woman cheats on a woman? If the woman's always to blame, who does the guilt fall to then?
Wait, never mind. Obviously it's both their faults for not settling down with a man like a good girl should. If one of them would just marry a man and the other act as his mistress, everything would be hunky-dory, I'm sure.