Why do I hurt people?

I'm pretty and intelligent, and so lots of people seek me out. I'm always excited at first and glad for new company, but I inevitably am disillusioned pretty quickly. So I leave people. Why am I so selfish? Why do I cause more pain than pleasure? Should I do something to make myself less desirable? (This is not a one-time thing. I've hurt 5 men in the last 2 months. And all of them have been sensitive men.)