I just don't know

I'm scared. I don't know that I could survive another heartbreak. How do you let yourself open up to some one, have feelings for some one, when you are afraid that as soon as you do, he will leave or change his mind about you? Then I wonder - how many other women is he dating? Kissing? I don't share. I know, I know, its only been three dates...but these are the things I think about. There is so much to know about him that I don't know. I realize that is why we date, but why does it have to be so hard? And hurt so much?