I’d suggest you buy occasional copies of a cookery magazine; Delicious and Good Food for example, which have lots of ideas for interesting and sometimes easy meals, both veggie and meaty which you might even enjoy cooking. For simplicity, Delia Smith’s How to Cheat cookbook was much derided when published but has some really good ideas. Also Jamie Oliver’s Take 5 Ingredients for simple but interesting meals without masses of ingredients to buy in if you don’t keep a store.
I’m a keen cook, though, and appreciate you might not be. My DH has vegetarian leanings but will occasionally eat fish, prawns or chicken. I find it best to make a basic meal, say a chopped onion/garlic/celery/carrots combo gently cooked till soft in a tablespoon or 2 of olive oil, you can then add spices if you want to, could make suggestions if you wish. Then add a can of drained beans, eg cannellini or butter beans or chick peas . Top his with prawns, a roast chop or chicken joint for him and a fried egg for you. And some chopped coriander or parsley for him! Or vary your chips with sweet potato chips, and your fried egg with an omelette with various fillings for him, actually easier than a properly cooked fried egg! Also most root veg and squash are very tasty brushed with olive oil and a little salt/garlic salt and roasted in a medium/hot oven for half an hour or so. Risottos (his rice things) are quite straightforward to do, and can be veggie or meaty, though you have to stand over the stove stirring for 20 minutes or so. Delia did an oven baked mushroom one, though not in that book. Hope this helps, good luck!
Can sympathise! DF lived with us for some years before he died, and all he ever wanted to eat was fish and chips, egg and chips and rice pudding, opposite problem, I suppose.