Why do men marry bit*ches? Or even Date Bit*ches? 10 points best answer!?

Sometimes I think I'm too nice in general. And it is not the way too be all the time. It can backfire, and I can loose good friends I feel in my life, or whatever. How do I be nice, but stop being so dang nice? I feel like it takes away energy from who I really am. Ya know? Think it has everything to do about how I was taught. But niceness can be a dang curse....just straight up curse. How do I be assertively nice but not overly nice to make ppl respect me and not try 2 take advantage of me? Is there anyone who can give me their words of wisdom? Howthey deal with certain ppl? Scenarios? Best answer gets 10 solid points! All the rest...you guys get great Karma =D thanks so much for your time!