I think, bottom line is.....men are going to gravitate towards you more when it seems like you've got it together and are comfortable in your own skin. Every guy I've talked to told me there's nothing worse than dating a girl that has so little going on in her own life that she latches onto them like a leech and expects them to fill all the gaps in their life (social or emotional, whatever). Yeah, they want to feel loved and needed. From what you've said though it sounds like you move on to the next guy and throw your whole self 100% into the relationship. It's just not healthy, and frankly it's a little intimidating to anyone that would date you.
I think you understand this, but now you need to get to the part where you can actually make yourself believe that men and love are not the be all end all. Maybe you need to go through a few more crap relationships before you'll fully get it, but let's hope not.
Live as if you were to die tomorrow. Learn as if you were to live forever. - Mohandas Gandhi