I suppose if a woman stays married to a cheater, she at least protects her children from having a wicked or hideous step-mother. That's the only reason I can think of for staying with a cheater. At least you don't send your kids off to "the other woman's" house for a couple weeks at a time, and not have any power over what happens to them there. What an awful situation to stay with him though!
I see women stay with cheaters for a number of reasons and the "for the kids" reason I think is among the least considered. What it appears to boil down to from what I can see is money/lifestyle, followed closely by the fear of being alone.
As for Step Moms, I really like my daughter's step Mom and find her to be a lot like me! But she wasn't my husbands mistress, so the dynamic between us is VERY different that if that were not the case.
On the subject of cheating it seems to me that educated, smart women have decided that they're "down" with being a sideline 'ho, case in point, Reille Hunter. What kinda 'ho brags about the affair, poses suggestively in a men's magazine, and goes after the wife? The kind that needs a royal, ol' fashioned a$$ whippin' as far as I'm concerned, LOL!!!!!!