Ah, you picked a subject that has been a forte of mine since I figured it out in college. The "Nice-Guy" myth. It's not between nice guy and bad guy. For many women and it sounds like for you it is not the fact that the bad guy is a bad guy that attracts you. Most guys who are the classic "nice guy" is that way BECAUSE THEY HAVE NO BALLS. Or BECAUSE THEY ARE BORING. Nice = boring. No spine. If they did, they might be mean! (In some cases.) Some nice guys are truly nice deep down but don't know how to care about themselves and stand up for themselves. If a man can't stand up for himself, how can he stand up for you? How can he check you when you're out of line, be a true equal and respected partner, and earn your respect? He can't earn the respect of an intelligent woman.
The bad guy is fun, exciting, interesting, sexy, and then, fiery, a jerk, an %¤#&!§-, etc. A woman who respects herself deeply will only let such a guy get buy with so much. So what to do?
The difficult thing to find is a guy who is fun, sexy, kind at heart but strong enough to be your equal. There is such a thing. I was incredibly lucky enough to find and marry a man who is soulfully kind when it comes to it... but not sappy otherwise. He has a backbone, can stand up for something, be a jerk if the situation warrants it (as in when he needs to put a bad employee in line), but even when tough, he is fair. And he's fun. He treats me well but is not boring, will not be walked over and is fun.
They are out there, nice men with a backbone and a little something more to catch your interest whether that be forward intense sexuality or a sense of humor. Anyway, that's my general take. The nice guy myth is that nice guys finish last and women want bad guys. The fact is that the standard nice guy is boring, uninteresting and unattractive to women, leaving them to be attracted to exciting guys who usually end up to be jerks. If you can find one who is not, then you've hit the jackpot. May you be wise and know the difference - don't take any crap!