Get someone she trust and looks up too, that person has to explain it, as long as they understand. She sounds like my wife, (all wives) your friend is an idiot to her, even though she loves him, he is still just a lying man and your his friend so your no better. Let the issue die for a little while, as frustrating as it is, then have her speak to an "expert", I have to do this all the time, as I to am an idiot, the person be it man or woman will explain it to her and BAM your good to go, even though the person is just reiterating the exact thing you just said a hundred times. That person his an expert not an idiot like you, remember don't rub it in, just take your victory home and load some ammo.
Or you could always cut her off from sex, that works to.