It has a lot to do with the "bad boy" image. "Bad boys" can trigger attraction in lots of women. The woman won't know why, because it's an unconscious feeling that has no logical reasoning to it. "Bad boys" have attributes that outweigh the "jerk" image. They appear confident and make decisions based on what THEY want. They don't seek or want approval and probably have strong alpha male body language. These are all attributes of a "leader" that most women are attracted to at an unconscious level. They are also unpredictable, which means that crazy, exciting things will happen at any time. There is no way they are boring. So a woman feels that she'll have fun and excitement with a confident man that will take her on adventures she can't imagine. If her friends ask her why she's with a man like that, she won't know why, because it's a powerful, gut-level attraction she can't explain or control.