Is it normal to be in love with my best friend if i have a boyfriend?

Okay, so I'm a girl and my bestfriend. Josh, we used to "talk", we almost dated even, but I said I just wanted to be friends. So we talked just as friends for a few months and I started dating someone else. When I told him , he was mad because he said he was in love with me. But now Josh is being very supportive. Now I feel that I made a mistake because it seems like I now enjoy talking to Josh more and just seem to wanna be with him. I don't know what to do because I like my boyfriend but it's all a mess. Help??