This is also us three nights a week. We eat a lot of very simple meals!
The things we do often are:
Jacket potatoes. You can cook an entire bag of potatoes in the oven on a Sunday and they last a good few days in the fridge. We normally just heat them up and have them with cheese and beans or tuna and sweetcorn. If we don't use them for dinners DH and I take them to work for our packed lunches so they don't go to waste.
Often on a Sunday I'll also cook something like chilli con carne and rice then either have the chilli on a jacket potato on the Monday or use it to top nachos, or put it in a wrap with cheese and pan fry it like a quesadilla.
We have a lot of meals on toast. Eggs, bacon, mushrooms, tomatoes etc or any combination of the above.
Soup and a part baked baguette or garlic bread.
Stir fry veg with noodles.
Omelette with salad.
"Fish tacos" which is just fish fingers in a wrap with lettuce and some sour cream or aioli but my DDs love. You can add chopped onion, coriander, chilli sauce etc if you like.
Lots of pasta dishes can be made in under 15 minutes. I often boil some pasta, add peas or sweetcorn to the pasta pan near the end of cooking then while the pasta and veg is boiling make a quick sauce. Fry chorizo and add garlic and olive oil then toss through the pasta, or prawns, lemon and chilli, or cook mushrooms and cream cheese in a pan loosened with a spoonful of the pasta water to make a sauce.