There are a few books written about this:
"Dangerous Men & Adventurous Women" is an in depth discussion about why Romance Novels account for over 50% of all book sales annually in North America and why women can't stop reading them, even women you'd never think would.
The Romantic Hero is a man that is strong and defiant, and her job is to tame him. He resists her, he acts brazenly and is wild. He is emotionally unstable and flies off the handle for seemingly no reason. It is this unpredictability that drives her wild. He tries to leave, go off on his own and be alone. In the end her love is so strong the beast is tamed and he can no longer resist.
Studies have shown that North American men are mostly tame and docile already, and women use these books to get a sense of the excitement and romance they have seen and heard about in movies.
The bad boys end up getting a lot of girls because he can take her on this ride up and down, that is sometimes a lot like a drug. unfortunately a lot of the times these men are physically abusive.
On the other hand, it also showed that most women end up marrying the nice guy, and being for the most part happy with him.
If you ever want to strike up a conversation with a girl and don't know how, hang out around the romance novel section at the bookstore. when you see a girl browsing the area that you want to talk to, approach her and say that you heard these romance novels were really popular, but you've never read one and were just wondering what some of her favorite ones are and why.. cause you'd like a suggestion.
in like Flynn