I felt like that with my last boyfriend. I enjoyed sex with him but wanted to see if it felt different or was more exciting with someone else. So I did. I broke it off with him. It turns out that I didn't really love him after all, and that I was just fooled into thinking I did becuase he was the first person I have properly had sex with. But that was me. I think it was just about sex with him anyhow, as with my new guy it is on a lot of different levels...