Have you been living under a rock? Yes! Women get hit on a lot! Every single time they're in public! All those places are familiar, as well as the gas station, the grocery store, the post office, the sidewalk... anywhere men and women encounter one another, that's where women will get hit on.
It's a good thing that you aren't so jealous that your girlfriend doesn't tell you. I had one ex-boyfriend who used to get angry every time a man hit on me if he was nearby. He felt that he had been personally disrespected, which always made me roll my eyes. He thought puffing up his chest and acting tough reinforced his "manliness" but it always reduced my opinion of him as a man every single time he did that. I've always felt that a real man wouldn't be so bothered by that sort of thing that he acted like an idiot.
I actually think TheBoyfriend enjoys it when other men hit on me. He seems to like seeing how other men act towards me and he seems to enjoy watching them fail to pick me up. It doesn't make him jealous at all. He seems to think it's funny.
My first encounter with this was the time I went to my friend's book signing party wearing a corset and leather pants that she had given me because she'd grown out of them and I didn't have anything appropriate to wear to a party like that. The book was just released and it was the first book signing, so there was a whole party, and it was a "corset and leather pants" sort of party.
I assumed that TheBoyfriend would stand by my side all night long, discouraging other men from talking to me like other men would do, so I didn't feel so self-conscious about going to the party dressed like that. Besides lots of other people were also going to be wearing racy goth clothes, including the author of the book, so it wasn't like I'd stand out.
At the party, TheBoyfriend did not behave the way I expected him to at all! He stood far away from me next to his best friend, watching me with an amused look on his face, leaving me to deal with the male attention that corset+leather pants+heels brings. Every single time I looked at him like, "Help!" he was just laughing at me. He seemed to be purposefully not standing next to me so that he didn't discourage anyone from hitting on me so he could watch the whole amusing scene from afar. I have to admit, his confidence in himself and me is very sexy to me, even though I was very annoyed with him that night.
I recommend that's how you should handle it. Watch it like an anthropologist. Enjoy the absurdities of male/female interactions. Enjoy the fact that she's hot enough that lots of guys hit on her, but she goes home with you. :smile: