Two things: big +1 to lentil's suggestion of doing "take out" from the grocery store. It's a big improvement for us (financially), to decide we're not cooking (usually because we're out running around and not actually at home at all) and head to the grocery store. A rotisserie chicken, some deli salads, and maybe a bottle of wine and we've spent $20-30 instead of $50-60, and we have leftovers for lunch the next day and then soup from the chicken carcass. It's not as frugal as roasting the chicken ourselves, etc, but it hits the spot.
We eat tons of eggs for dinner as quick meals. During a couple of our busiest weeks around here, I was eating 3 fried eggs on toast almost every day for dinner, and DH was fending for himself! I figure if I'm still eating fruit and veg throughout the day, the occasional day without a balanced dinner isn't the end of the world!
My other suggestion for the situation you're describing is what my family did when we were growing up. I think those end of the week family movie nights are really great and having those rituals is awesome too. Growing up, my mom and dad would cook the staple dinner rotation through the week. Pasta, sheet pan meal, maybe a curry night, a stir-fry, whatever. Leftovers would go in the fridge and sometimes get nibbled on for lunches, but we would often have sandwiches or other stuff for lunch. So Friday was leftover day! All the containers would get taken out of the fridge, heated up, and then set out on the table buffet-style. Presto! Restaurant night. We could all pick what we wanted for our own plates, maybe add something special/ unusual to us (like sodas or potato chips or veggies and dip) and we had a fun, relaxed family routine.
These days I mostly try to cycle leftover ingredients through the week so as to minimize our food waste, but we're only 2 adults now, so maybe the above would work for you. :-)