Why do women see a man cheating the same thing as them cheating?

I deplore cheating of all kinds. However I do agree with number 2. If you don't show your true colours before you trick someone into marrying you, you only have yourself to blame for it if the relationship disintegrated. That's why I'm against marriage to a certain extent - when the threat of a breakup still hangs over your heads, both men and women have to keep themselves attractive and ually active.