Should I be bothered by this about my girlfriend?

So basically, I'm a little bothered when she talks about how hot some other guys on TV are to me. As an example, we may be watching a movie, and she says she thinks he's got a cute face, or a hot butt. I don't know, it's pretty small stuff in retrospect, but I guess I'm just a little bothered that she tells me how she is attracted to another person.

I understand that people can be attracted to other people,and yes, I am as well, but I don't think I feel the need to tell her about how I find another girl's face pretty or how she has a nice ***, as well (I never have told her things like this by the way). I don't care that she thinks it, I just find it a little uncomfortable when she tells me these things, because I tend to think that it is a bit rude to the other person.

Yes, I've told her this before and she seems to keep doing it, perhaps to tease me. I don't know, maybe I'm just being foolish.