That is one area that I can say I am successful in .................being organized.
My DH was a packrat too......I de-packratted him and converted him. But that did take 17 years
I simple stopped buying STUFF...of any sort. That helps stop the stacks and piles.
Sort mail over the trash can.
Then you can start on YOUR stuff - your closet, etc... You'd be amazed at what you'd find then have a garage sale
I have found having less clutter is so relaxing.
I do have things on the walls, but my walls aren't 100% completely covered and my house isn't over decorated, again.....I find it relaxing.
Maybe your DH might find it less stressfull and more relaxing to play computer games in a cleaned out house