I think when they're younger they prefer the bad boy but as they get older they prefer nicer people. The whole 'bad boy' phase gets old after a while and it doesn't take long for people to realize that you're only doing it to essentially show off. Dick measuring if you will.
This, and science arguably backs it up.
On the purely biological level, women tend to gravitate towards the masculine ideal of manhood, because there's an underlying unconscious perception that a handsome badass is probably pumping out quality DNA that's going to have added advantages to help the kids survive in a harsh world. But once they're pregnant, women no longer benefit, so their hormones actively turn them away from the "bad boy" and more towards someone who's actually going to stick around and help care for/raise the kids. It's part of why the stereotype has always been that girls in their teens and twenties want to date the rockstar boyfriend, while women in their thirties and forties are mostly looking for the stable "husband material" guy.
(This is also why the masculine ideal is becoming so, well, "unmasculine" lately - there's multiple theories that the advent of the birth control pill in the 60s/70s has effectively skewed women's biochemistry towards the illusion of being pregnant all the time, thus preferring the dependable nebbish over the unreliable badass, and that Western culture as a whole is slowly starting to shift to match that new alignment.)
People can dismiss that out of hand with "Oh, that's all instinct and habits from thousands of years ago, but now we're totally self-aware and able to evaluate our own choices and make decisions based on logic rather than pure animal instinct", but people in general are woefully naive about just how much our own innate biology and evolutionary tendencies DO shape our behavior (in countless ways other than just mating habits), no matter how much we try to convince ourselves otherwise. In a lot of ways, we're basically computers made out of meat and neurotransmitters.
And "lust" is one of the least logical, most instinctual reactions modern humans HAVE (with blind rage as a maybe close second, or just edging out first place) - so if ANY modern human behavior was going to function in the same way it did hundreds of thousands of years ago, that would be the one (with things like aggression and eating being other, deep-seated biological programs hardwired into our brains).
The flaw with this argument is that the "bad boy = masculine" idea isn't universal amongst cultures. Most English-speaking cultures follow it, but plenty of others do not. If it truly was driven by biology and not sociology, it shouldn't be dependent on culture. ---
Kill 1 man: You are a murderer. Kill 10 men: You are a monster. Kill 100 men: You are a hero. Kill 10,000 men, you are a conqueror!