Why Do Guys Look At Other Girls When They Have A Girlfriend?

Because they are visual creatures, girls check out girls just as much, even if you saw a gorgeous girl you would look, but it doesn't make you ANY less important and special to him, He wouldn't be with you if he didn't find you attractive or have that connection in anyway. If it bothers you that much, don't let it escalate to the point where you just want to dump him, Next to catch him out doing it and tell him on the spot that you don't appreciate him perving whilst you are there because it makes you feel as hot as her....Once he understands, he should respect your feelings next time he goes shopping with you or wherever you go, and if he doesn't respect your thoughts, then time ti give his pathetic ass the boot!

Well, I really don't have any clue, though I never did so ever, as I never had to with my girl around or away from me.. She is the best for me... No one can come near to her...

It's just their human instinct. A lot of the time, they mean no harm.
I believe that it is highly unlikely that you have never looked at another man and thought he was attractive while you were dating someone.
As long as you are happy in your relationship, there would be no need to worry.

Hi Shuba,

you are girl and can you please tell me frankly you don't see any other boy in the absence of your b/f. If you are a true person then please tell me the truth, I know its hard to tell that you also look other boys but the truth is truth. Do you know that every person is not perfect or 100%, every person have some lackness so we always want to see that.
if your boyfriend is looking other girls then try to find out the exact reason why he is looking others. Tell him that you feel very bad about that...try to explain him that you love him a lot.
thanks

It's all a matter of male instinct. Most males love the shape of females because they think of them as if they're a piece of art. But other than that, what Maddysays just mentioned

Human nature.
Don't act like you are ms.perfect

Because they have already seen to much of their girlfriends and are looking for new things to explore