You think thats bad?
I have a mate that keeps flirting with, Hugging, Trying to grope, Buys drinks, Cuddles into her on the sofa with my CURRENT girlfriend!
And what does your gf do about it??....does she tell him off or does she sit back and enjoy his attention??. If she tells him to back off then you need to step in and tell him its not on and if he doesnt back off either stop hanging with him or pummel his face in so he gets the message....if she actually enjoys the attention then you need to dump her skanky ass and get yourself a gf who appreciates the fact that shes in a relationship.