Boy, I don't know. It sure seems that something happened to scare him that first time when your gf walked him. I would keep taking him back to that same spot & making him sit/stay. I don't think it has anything to do with trying to protect you. Have you tried a Gentle Leader collar? It's like a horse halter for dogs. They are terrific. No more chocking them around the neck. For some reason dogs behave much better wearing one. You are controlling their head, & where their head goes, their body follows. Caesar uses them once in a while. I urge you to try it.