You should advertise to lease him to someone. Then, he is still your horse while they use him. Make sure to put in your add that he needs an experienced rider due to his trust issues. You can write out your own contract dealing the duties of the leasee (care, your visitation right, etc) and you may charge as little as $1 to lease him or as much as you want. Leasee's are in charge of feed, farrier, and vet care with their leased horses just as if they owned him/her. You can set the lease terms to a certain amount of time, whoever long you want. Make sure however, that you like the person you lease him to and feel safe that he'll be taken care of. Visit their home/facilities, and watch them ride him. If they have other horses look at them to see how well they are cared for. Ask for references that you can call and talk to about their personality, habits, horse experience, etc.
I've known peole who have leased horses and its great for the leaser and the leasee. Alot of people who want to ride but can't afford to actually buy a horse look at leasing. 4-H members and pony clubbers would die for the chance to lease a stellar pony performer. Just make sure they are an older more experienced member if he needs it.