Why do we make girlfriend or boyfriend?

Please I am serious here, when I look at any girl I think about sex and being nice and romantic to her. But I am afraid to make any emotional attachment by heart. But it is not working because I think why would any girl would like to screw with me if she finds no emotional attachment by my side. I was broken-heart once,so my mind doesn't allow me to feel that emotional attachment with anyone and only want to use someone for sex only. But my heart know that it is wrong because I have never been in a relationship. My heart wants to experience the love and thrill of being with someone who would care about me. But mind takes control and I am scared that something could go wrong again and might get heart again. It is like a splinter in my brain and I wonder why do I make