2 - Some women are attracted to those seen as a 'challenge', some kind of project they can take on. Those girls think that they'll turn the wild boy around this time, because their love is special. It's actually some form of dependency based on some emptiness those girls have inside. 

3 - Some girls like bad boys because, deep down, they don't want to commit to a really loving, committed relationship. It may all be subconscious, but it happens. 

4 - Finally, it may just be that some girls prefer a complicated guy because their life path together may be more interesting. Working harder in a relationship also means working harder with ourselves. This last category is probably the most acceptable and the one you could be working towards. Sometimes we try to be 'easy' to a point that we're no longer ourselves; we've buried our passions, our idiosyncrasies, our fears, our dreams so deep down in ourselves that all we have left on the surface is this 'flat' human being walking around and living life in a discouragingly predictable manner, without passion nor excitement. By that I don't mean you must turn to sex, drugs and rock and roll: in fact, as I mentioned above, women who tend to go for truly 'bad boys' have serious psychological issues they could probably address for their own benefit; this because the greatest majority of the time those bad boys will not be able to love them as much as they'd want to be loved, starting a vicious cycle of pain, dependency and psychological addiction. 

But what you could do, as a first major step to become one thousand times more attractive to girls and women, is to find your real self, let it out regardless of what others may think, be true to yourself, resume your passions, dreams and desires, and live them every day. You will see how you will metamorphose into really interesting guy who will attract a much larger number of women. And, because you didn't turn into a 'jerk', you will actually attract emotionally more balanced girls rather than those seeking to fill a void.