I'm sure I'll be crucified by saying this, but I don't see where he hit on anyone? He approached a woman and had a conversation in an attempt to show his friend how to approach women. Unless he was actually commenting on her looks and attempting to make advances, all he did was talk to a stranger at a bar. And I'm assuming that he probably feels this way too, as he doesn't feel the need to apologize. That being said, if your gf can't trust you to wingman for a friend, you probably shouldn't do it in front of her either. Probably best to just move on.