The right question is why should a woman get married to that person who treats her like crap and followed by why should she stay married to that person without any hope of him ever treating her right.
I look at marriage like an investment where you invest your life, your time, your present and your future. In return, you want love, respect, a trustworthy companion for life and a good partner to raise your children with.
Now say, in spite of investing all you had, you get crumbs. Any advisor would tell you what a shitty investment that is without any return.
So any smart person would pull out whatever investment capital they have left and invest them elsewhere, for example on your own self for your own happiness. So yes, you may not have a trustworthy companion right away (or may be you can get a dog), or a good partner to raise your children with (but you will have full control on how to raise your children right). But love and respect will be plenty since you would learn to love yourself first and respect your self. So better return on investment than a shitty partner, no?