Im sorry for your situation, that's a rough row to hoe.
I have done much of the cooking for us, my wife does on occasion but its a chore for her much of the time and I kinda like it. And we arent losing any weight because of it so it is decent eats......
But when she is gone for something I usually dont go out of my way to do something as nice as I would as when she is here, Im 'easy' to satisfy; not that she is hard to, its just that I dont put as much into the effort for only me. This, and the other stresses you are under and no one to share the fruits of your labors with make it tough to 'make a real meal'. Did you like to cook before? If so, the skills and knowledge are there and maybe you need a kick start to get back into the discipline?
I encourage you to do so, it is good for the body, mind and soul. Paring back recipes by half would make for not having to eat the same leftovers for too long (and its good to mix 'em up day to day anyway). Buying 'family' size packs wont save you money if you throw half away, just get smaller/individual sizes for a while and see if you can sort it out a bit. Just making it yourself will save probably 1/2 over doing 'fast food' (bad habit but so easy to get into).
I make a goodly number of 'scrambles', use leftover real baked spuds diced up with diced onions and jalapenos, etc. with some microwaved bacon/ leftover meats/ diced precooked pork or turkey b-fast patty and topped with real hand shredded chunk cheese (much better cheese than the pre-shredded), or a nice omelette with similar.
I like to do a basic simple chili that I can have a bowl of anytime in an amount that lasts 4-5 days in the fridge.
A 'cottage pie' of a layer of good pre-cooked loose burger covered with a layer of diced onion, carrots and celery (could use canned but fresh is so much better, just be sure to nuke it all to cooked before spreading on), a can or two of cream of mushroom soup and topped with a layer of easy to make on the stovetop mashed potatoes (I get the smallish box of generic spud flakes) with shedded cheese on top and baked for 1/2 @350 makes me a comfort food casserole.
I still like a good hamburger on a good bun with fav toppings.
Remember you are not only doing this 'to eat' but to keep yourself healthy for her.
I'll be praying for ya!