Uh huh, that's why Kim is still his GIRLFRIEND. Have you ever wondered why they arent married?
It is probably because when you cheat when you are married, it is grounds for divorce. And she could stand to make even more money in alimony + child support, then just child support alone - regardless of living with him.
If she knows he's cheating and she hasnt left him, she's either an idiot who thinks he's gonna change or a very smart woman milking the relationship for all it's worth.