Does he give you any warning? Playful nudges, head tosses, shaking, etc? If so, you need to redirect that 'bored' energy, by putting him to work...because he is biting, I suggest that you get him to work longing, as that will get him away from you during that energetic time.
Always carry a crop with him, and carry it in your lead rope hand, so that you can use it to 'push' his head and neck away. It's hard to explain, but what you will do is walk with the crop 'up' and in a position that he can 'visualize' it as a barrier to you. If he tries to invade your space, swing it back and forth; it may take some practice. He will probably wind up getting whapped by the crop a time or two by the time he figures out NOT to invade your bubble, but hopefully, he will figure it out, so you don't have to continue avoiding him.
You may also want to find a trainer who specializes in problem horses, especially if this guy is so obnoxious about his bitey behaviour. A biting horse is not a fun animal to have, especially because they are so large an animal...get some professional help, before you or your family gets hurt more. Leaving the horse 'alone' isn't the answer either...he needs to be worked with, as the habit won't simply resolve itself!!!
"The ideal horseman has the courage of a lion, the patience of a saint, and the hands of a woman..."