the front of the head can take quite a bit of punishment, whereas the back of the head cannot. You can get in several stikes to the face and head area without causing permanent damage, but stay away from the the back of the head.
Also, it only takes about 11 pounds of pressure to remove an ear, so if you have to, you can rip his ear off and hand it to him, without exerting yourself or breaking a sweat.
Of course, there's always the humiliation factor. Go to your local farmers co-op and pick up a cattle prod, then use your imagination. It's great fun to hear men squeal while you're zapping them with the prod.....after a couple of jolts, a well placed jab and a finishing punch to the jaw area will complete your lesson in violence. I doubt that after all of that, he'll be pestering your girlfriend.
