To avoid cooking two meals a night, I would cook a big thing and everyone eats that for 2-3 days.
Suggestions:
big lasagne, chili con carne, moussaka, stew, curry, veggie curry, slow roasted pork shoulder, pasta bake, mac 'n' cauli cheese, cassoulet
Switch up the sides from night to night in order to prevent whining, for example serve the above (as appropriate) with one or more of: salad, flatbread, garlic bread, steamed vegetables, baked potato, potato salad, wedges, mash, chips, sweet potato, sauces etc.
So, for example:
Day 1. Chili with rice, salad and refried beans
Day 2. Chili over sweet potato chips with salad, avocado and salsa
Day 3. Chili with rice and beans in tortilla wrap