Why is it worse when a lady cheats?

Women have always been in the "power position" to say no to sexual advances. At the club, parties, office, neighborhood and anywhere else you might think of. They know it and even take pride in it...meaning women can say no! On the other hand, only the 'principled and decent' men have been known to turn down sexual advances for reasons pertaining to faithfulness! That is an open secret. Many men's brains turn temporarily uncontrollable when it comes to sexual intimacy and they seem to be on a "psychological auto-cruise with gears in overdrive).
Therefore when a woman cheats, its premeditated! So simple! otherwise, she definitely could have gotten out of that situation.

The questions now become "why did she do it?", "what did she want from it?", and all sort.

N.B. - this is a MOST CASE Scenario.