Howard, you are suffering from the mild depression that sets in when you realize that there is no point in getting big and strong anymore. Age has a way of doing that to you. So back off on the weights and enjoy life. One heavy workout a week will maintain your muscle mass. Life is too short to worry about things which dont matter in the grand scheme of things.
After 3-4 marriages, being a high school teacher, and seeing the guys you taught come back and be bigger than you'll ever be, I think it's high time he take up another hobby, like fishing, wood-work, painting (Bob Ross Style), drawing, law school, buy a Porsche, fix up an old car, learn to dance salsa or samba with the wife (women get in shape from that)...
Or sit on the couch and watch the Oprah Channel.