It sounds like ground work is just what you need! Make sure to do a lot of practicing on him giving you your space, and if you give an inch he may take a mile so be very clear about your expectations for when he will walk, when he will stop, and how far away from you he'll be while leading! Steadily increasing commands are a good way to work on most ground work. Give a gentle command, and continue to increase your command if he doesn't listen. That doesn't mean beating your horse, obviously, it just means to increase the cue. Clinton Anderson style with the increasing pressure, if you have read/watched any of his stuff my post might make more sense.
A horse is the projection of peoples' views about themselves--strong, powerful, beautiful--and it has the capability of giving us escape from our mundane existance.