personally i agree with p8ntcrazy
i can bet you anything that the horse is just feeding off of your energy-- your afraid to tie him, so he's going to be afraid to be tied
i had a bit of an issue with this when i first got brogan
i tied him with a quick release knot that you can do with any lead rope-- if he pulled, i pulled the knot loose
i would do this with him for about an hour every single day and eventually he realized that it wasn't a big deal at all