I'm hoping that I don't insult you with the basics of backing a trailer, but the first thing I learned many years ago is to put your hand on the BOTTOM of the steering wheel. Now, if you want the rear of the trailer to move left, then move your hand to the left; if you want the rear of the trailer to move right, then move your hand to the right. This helps overcome the mental disconnect of moving your hand the opposite direction that you want the trailer to go.
Another tip to save your marriage is to get some walkie-talkies for you and your wife and teach her how to spot the trailer for you. Define terms that you each understand (trailer to driver's side; trailer to passenger's side, etc. are some we use), and help your wife to learn how quickly the trailer will react and how long it takes to get the truck straightened out to get the trailer turning the other direction - my wife had to learn that if the truck is at a 30 degree angle to the trailer, the trailer isn't going the opposite direction until the truck passes the straight-ahead position. You "cut" to get the trailer headed in the direction you want, then you "chase" it with the truck before it over-reacts.
If you have access to an empty shopping center, big box store or strip mall, set up some cones and practice, practice, practice. I started towing 5th wheel RVs back in 1996, and I know how you feel - I couldn't put that thing into a site if I had a 40 acre field to work with back then. It's an acquired skill that comes with experience. Now I back our rig into our covered storage site that probably has 1-1/2' to 2' clearance on each side without any problems.
Rusty