Why do some girlfriends act like mothers to their boyfriends?

Anonymous
So maybe it's the age group I'm in, and there is still a decent maturity gap between the sexes, but I've been noticing this trend among my friends. The girl in the relationship seems to either have almost complete control over the guy, or the girl both provides a lot of things for the guy and tolerates a lot of childish behavior, while enforcing limits.

Why does this happen, and further, why are these girls content in relationships like these? I don't believe there's anything wrong with a woman having power. That's a given. I was simply under the impression that a girl would want someone who is more of a companion, an equal, a partner, a man, rather than someone they have to drag around or baby all the time. What's up with this?

My hypothesis is that it has to do with the girl being sick of rougher guys who are not controllable and selfish. When one of these girls finds a nice guy, she will tolerate some of his shortcomings and make sure he turns out right so that once he matures, she'll have a good man. I've never been in a relationship like that though, so I really can't know. What do you think?
Why do some girlfriends act like mothers to their boyfriends?
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