We had to put down our most recent boxer two years and four and a half months ago. As he got older, my wife was afraid he might fall down the steps from the deck so we had to close and block his doggie door, then begin walking him in the backyard. When I would take him outside in the deep dark night we often just stood there under the trees communing with nature as Boon Companions.
Dogs need to be allowed to do what they want to do, to the extent possible. Otherwise. the energy is diverted to undesirable behavior. I used to have some worthless neighbors that had Springer Spaniels. I don’t know why they had them. One of them was always on a rope tied to a pole in the front yard. It ran in circles barking and got tangled like a tetherball. I was always pleased when it got loose. It ran across the street into the woods, and disappeared for hours. I’m sure it was trailing deer and quail, and was as happy as could be. It’s a tribute to dogs that it even bothered to come home to those a-holes.
You wife was probably right to be concerned. I remember some people that had a boxer. Their kids taught it to bounce on the trampoline with them, and sometimes when they wee in school, the dog would just go out and have a good ol’ time bouncing by itself.