At my job I usually have to work a bunch of horses. What I will do is pony one while I do flat work on the other. Then when I am done with flat stuff I will tie-up one and do more specialized work on each or switch who is getting ponied. Sorry if I totally chopped that up. Make sense?
Or maybe you can teach your husband some things to do with him this way you only have to jump on him a few days a week instead of all the time.