Cats have to scratch. It is necessary not only to keep their claws sharp. It is also necessary for their sanity. If they are prevented from scratching by overzealous owners trying to save their furniture and drapes, they will become anxious, irritable, depressed. Then their owners will become anxious, irritable, and depressed too. So let the cat scratch. Go out and buy a super-deluxe scratching post, drench it with catnip essence, and put it away in a closet. No self-respecting cat is going to stoop so low as to scratch where its owner wants it to. My advice–let the cat have the couch. And whatever else it wants. Then all will be happiness in the house.