Most nights - I'd say maybe 5-6 nights a week? I don't do complicated meals every night, but honestly, I think a lot of ready meals taste like crap, so for the same cost or less I'd rather make something myself. On Friday and Saturday nights, we have a date night meal alone after our daughter goes to bed, so on these nights, she's more likely to have fish fingers (though even those sometimes I make myself, it's really easy) or a mini pizza or pasta and cheese or something quick and simple, and then we have something ourselves later, which is sometimes a ready meal or takeaway. But the rest of the week I cook. There are loads of things you can cook in a fairly short amount of time that are tasty and healthy. I get home about 5:15 from work and picking my daughter up and we eat about 6:30, so that leaves me about an hour and 15 minutes to make something (she helps so we get to spend time together or plays with daddy or vice versa).
On the nights I need something really quick and simple, pasta is great and easy. Sometimes I use a jarred sauce, sometimes a passata and add a few things to it, sometimes just garlic and cheese on top, along with some veg (either sauteed or roasted). So much veg now you can get just out of the packet (french beans, spinach, tenderstem broccoli, mushrooms, whatever) and I just dump it in a roasting pan with some olive oil and garlic (I get the pureed kind in the squeeze tube) and it's in the oven. That's a meal and it's pretty quick.
Last night we had salmon with mash and peas. Also pretty easy. I make salmon goujons (chunks of salmon dredged in flour, then egg or mayo, then breadcrumbs and then roasted until crispy), which are really quick to make and nicer than fish fingers and we all like them. Mash is pretty easy, it's just dumping it in a pot to cook, or sometimes I make rice, which is the same. And then the peas I just microwave from frozen.
Blended soups with bread and butter are good too. Also, easy, you just dump everything in a pot, boil til soft, and blend. We're having this mexican tomato soup for dinner tomorrow. https://cowfacemagazine.com/mexican-tomato-soup/
We don't cook a lot of meat (maybe once or twice a week?) so I think that helps. I think vegetarian food is a lot faster to cook and not as complicated. And I try to avoid things that need a lot of attention, like risotto because it's unlikely that I'll be able to stand over something and stir it constantly. The slow cooker is good too and I do use it a few times a month.
When I do have something more complicated, like tonight we're having cauliflower cheese and roasted root veg, I try to find a few minutes earlier in the day to get a task done. Like today before dinner time, I'll have to take 15 minutes and chop all the veg for roasting because it takes a hour in the oven and I'll need to start it right away. But I can always find a spare 15 minutes somewhere (I work from home, so I can do it while I'm making my lunch or my husband will do breakfast so I have extra time to chop veg for the slow cooker or to be put in the fridge for later). And then there's the white sauce to make, which is kind of a pain, but it's okay because I don't make things that need this much fussing over that often. So I plan them for days when I know my husband won't be home late, so he can take over and I can make the sauce. You can also still use a jarred white sauce, but I don't think it's as nice so I don't mind taking the time to do it.
That said, if it's just the two of you, I'd make something simple. We both travel for work regularly, so when it's just one of us at home, we usually do simple meals those nights when we only have one set of hands on deck. Either something that makes good leftovers, so we only have to cook every other night, or a quick pasta with cheese and peas, or something like sausages that just needs to be chucked in the oven and served with leftover mash and frozen peas. I don't think I'd make anything too involved on those nights.
Serve with rice or roast potatoes.. You could also make your own pasta sauce and freeze in muffin tins, then pop them into a large ziploc bag, single sized portions for pasta 
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