Mismatch

Can someone explain this to me? Why is it that wonderful, smart, self-made, successful women end up paired with men who are not only out of their spouses' league, not only fail to appreciate how lucky they are to have been chosen by these women as their partners but on top of that behave with the undoubted belief that they are the best thing that can happen to a woman. I've witnessed that phenomenon so many times that from simply bizarre it has become scary. The only question that really puzzles me here is: why do these women stick with these men? Low self-esteem? Distorted self-consciousness? Complete lack of self-respect? Why being in a dysfunctional relationship just for the sake of being in one matters so much as to put up with it? Sure, I'm not an expert in relationships but the way I see it neither are these women.