I don't think that there is any way to retrain a dog. When your back is turn, he will revert to his old habits. I saw this on QVC:
http://www.qvc.com/Sure-Fit-Reversible-Faux-SuedeSherpa-Sofa-Furniture-Cover-wPockets.product.H203786.html?sc=H203786-SRCH&cm_sp=VIEWPOSITION-_-1-_-H203786&catentryImage=http://images.qvc.com/is/image/h/86/h203786.001?$uslarge$
It look really nice and covers the furniture completely. It is easily washable. He does think of himself as a member of the family. I had smaller dogs and the only thing I insisted was they go potty outside. No accidents happened until they were elderly after all, they were after all my children. Hope you find something that works for both of you.