I'm a married med student who's always looking for ways to fit in diet & exercise, so here's $0.02 ...
One side of the equation is controlling input, so I'll carry a little tupperware dish, spoon & packet(s) of instant oatmeal in my bag, and nuke up one when I have a minute ... works well until one of the packets gets broken in the bottom of my backpack ... I also buy chicken breasts in big packages, quickly dump each one into a ziploc bag and freeze them, then take them out individually the night before to prepare on my way out the door. Can be as simple as cutting one piece into slices, covering with Italian salad dressing and nuking for several minutes while I'm getting ready, throw into tupperware and cover with some frozen vegetables, nuke later for a protein + veggie lunch. Also, lots and lots of coffee. And I carry a water bottle, or leave one in places where I spend a lot of time. And I like those frozen 'lean gourmet' meals, will stock up when they're on sale. It's just a matter of pre-planning, and wife can help out a lot (I'm a wife, my hubs helps me out, I'm not being sexist 🙂)
The other side of the equation is energy output, i.e. exercise; I bike to 'work' when weather permits, or work out at the gym nearby at night before going to sleep; you could work out with the wife for togetherness and mutual fitness; I know someone who without fail goes straight to the gym from work and hits the treadmill for 30 minutes in their scrubs. Hope these ideas help ... may seem a little obvious I suppose, but it's just a matter of finding little things that work for you and your wife. G'luck!