I finally tired of the battle. He knew it was unacceptable and yet he persisted. I felt a stronger deterrent was needed. I did not kick him in the teeth, he just got a strong tap on his nose from the end of my boot.
I gave him every chance to stop the behavior. He choose to keep it up. Horses are not idiots. When he realized it was not comfortable to bite me he quit.
And was a lovely horse btw. Just a tad spoiled for a while.