Most Helpful Guy
I think it's in the nature of guys to look at girls. When I'm just walking through the city, my eyes are always drawn to the best looking girl around, and that doesn't change when I have a girlfriend. When I'm with a girl, I focus my attention on her (she's the most beautiful girl around, anyways). This is all just instict and there's nothing wrong with it. Trying to surpress these instincts will only make you frustrating.
Talking to other girls is fine too, as long as you are clear about the fact that you have a girlfriend. Stay away from flirting, because it will lead to cheating and cheating is really, really bad. You can always have normal conversation with a girl.
If you really want to flirt with other girls, than maybe having a girlfriend is not your thing. When I'm with a girl I really like I don't think about any other girls and just enjoy the moment. Hope this helps.1THIS IS NOT RELEVANT ANYMORE