what does this mean?

Okay I just wanna know if anyone else finds themselves thinking about girls when they're turned on. I'm happily in love with my boyfriend but whenever I'm getting off I like to think about girls?? I don't think I'm gay because I've always wondered but I've never felt the love and attraction to a girl that I have for guys. But what's weird is that I'm scared to rush into things with my boyfriend, and when I just imagine doing the same thing with a girl it doesn't seem as scary. Is this supposed to indicate something or is it just because with boys it is more serious and more real and that's why it's scarier?