women at bars

So Joe and I were at a local bar Friday night. He loves Karoake and the bar also has the buzz trivia game so we usually go there on friday night so he can do karoake and we play buzz trivia. we were sitting at the bar most of the night and he went down to the dj to put in another song he wanted to sing. there was this woman down there and her friend joined her. i saw him pointing up towards me. later he told me the one woman told him her friend was single. he said he had a girlfriend and told them they had to have seen us together. she said her friend was fun. he ignored them from that point on put in his song and came back to sit with me. this is not the first time this has happened. he has been asked to dance by other women, etc. he is constantly hit on. one woman even tried to give him her phone number right in front of me. he and i could not believe it. we have yet to figure out why these trashy whores are so attracted to him and why they would even try to pick him up knowing he has a long standing girlfriend. we have almost dated a year now and we live together and most of these women know that. i just don't get women or men who would do this. there used to be some class and you did not go after anothers man or woman. not only that most of these women are in their early 20's and he could be their dad. i mean we both look like we are about 10 years younger than we are but come on. such bad manners now adays.
So I was telling a couple of my male coworkers about this and they said it happens to them all the time. they are both married and they said it is the attraction of what you cannot have. that the women know they cannot have joe so the attraction is even higher.. weird...