1.) Have you taken GOOD riding lessons on an experienced horse with a GOOD instructor? Do that if you can. Improve your riding and your confidence because your confidence or lack of confidence will transfer to the horse you are training. If you can hook up with a GOOD trainer through a good lesson program you might want to do that. IF you hire a trainer WATCH HIM/HER work with horses that are NOT yours before you send yours!!! The trainer who told you to get rid of this horse probably was not of a good class (lots of ppl say they are horse or dog trainers and they should be doing something else.. riding ATV's and keeping stuff animals.. because they should not be working with live animals).
2.) Can you build a mounting block? Do that. This way you can teach your horse to come up to that mounting block and he can get used to your over top of him. Your position up high (on his back) coupled with the new feeling of weight on his back are why he is spooking and dancing (plus your nerves feeding into this).
3.) Long line him.. drive him from the ground. Get him used to a bit or a side pull. I like a side pull or a half breed myself when I see this horse and you with him. After he knows how to turn and respond to the side pull or snaffle bit or half breed and when you ride him steer him by separating your hands and pulling out to the side (called using a leading rein) on the side you want him to turn towards.. while moving the other hand forward to give slack on the side he is turning away from. Eventually you will be able to keep your hands together over his neck.. but he is learning and so for awhile you help him all you can and use a leading rein.
4.) Get an appropriate properly fitting helmet and wear it. You are breaking in a green horse and green horses are not predictable. Wear safety equipment to protect your head. You cannot ride or do anything if you get hurt and believe me.. from what I am seeing of your riding skills you should be wearing a helmet. I am not saying that to diss you.. I just see a pretty nice horse and would hate for you to get hurt and that horse to be sold down the road.