Now first and foremost, in our house my DP does the 'wifework' - I am scatty as fuck and have reasonably low standards for housework (I tend to think it will become apparent when things around the house need doing and will deal with it when it does), he is hyper-organised and has to plan everything in minute detail, so we have a distribution of labour where I do any jobs that actually involve talking to people (sorting cleaner, organising tradesmen, nursery and school issues, childcare, dr's appts etc) and he takes care of everything that involves organisation and planning e.g. laundry, dishwasher, home improvement project mgmt, financial planning etc. I also probably do a little more childcare than he does, again because of a difference in our perspective as to what's required (i.e. if DD calls out in the night I will go as he a. doesn't wake up and b. thinks she's old enough to sort herself out now at 3yo, and I get up with her in the mornings as he's useless to himself before he's had breakfast, coffee and a shower, and it's nicer for everybody for him to get those before he starts engaging with the rest of us :P).
My point is, he is not a baddun like you read about on MN - he has his flaws, I have mine, and by and large we work around them and function well enough. Nevertheless....
Having cohabited with my partner for about a decade now, and knowing many other women/mums of small kids who do the same, I think the optimum living arrangements for raising the human species is collectives of women and their children with men visiting from time to time 
like elephants. I can't think of any woman I know with children and a male partner who doesn't spend an inordinate amount of time 'looking after' the other adult - be it the classic wife-work of housework and organisation or having to continuously deal with and work around their moods, obsessions, hobbies or sexual desires. Or both if you're really unlucky!
Men generally speaking (NAMALT!) just remain so resolutely themselves, so focussed on (and feel entitled to focus on!) what they want and need; parenthood doesn't transform them and they actually see no reason why it should. Whereas women with kids tend to understand inherently that the priority is and should be the needs of the small children, and everything else sort of goes into abeyance for a bit.
When you're childless and have time for the inevitable nonsense (arguments, sulking, making up), the joys of cohabiting are usually worth it - I remember a lot of spontaneous and frequent sex in unusual places, going out together, cooking together, sharing interests, decorating etc etc. But once kids enter the picture unless you are very well supported by a wider family/community network (of mostly women) maintaining a relationship with someone who is, in their own way, just as needy as your child can start feeling like just another job. Probably for both parties.
I'm aware there will be a billion happy parenting couples now saying how wrong I am; but I can't be the only one who'd love to spend day to day life living in a big house full of my mum mates and our kids for the next 10 years or so, and go on the odd sexy date with my DP, rather than spend so much of the time getting on each others' nerves and not quite seeing eye to eye on what's important. When we do manage to get childfree time I remember how lovely he is and why we got together, but when I'm constantly feeling pulled between his needs and toddler's needs, and feel like absolutely no-one is aware of or prioritising mine, it does breed frustration. But then he would say I have a tendency to martyrdom and should take responsibility for insisting on my own needs and wants (he includes in this taking a firmer/more hands off approach with our child than I'm happy doing; I'm not sure he would appreciate me doing the same with him!).
Covid does make it more difficult - he would sometimes go away for the weekend/work or whatever and I could purely focus on DD in the daytime, then when she was in bed I could do whatever I liked, i.e. lie in bed reading until 9pm then go to sleep instead of staying up trying to be amusing, I can listen to radio 4 all day long without him huffing about the naff radio dramas - basically what I would do if left to my own devices - and it acted as a really good release valve, for both of us I suspect. Being together literally ALL THE TIME (both wfh, can't go visit others) is testing the mettle of most cohabiting relationships at the moment I suspect. I think both of us are not quite happy, and both of us know it, but both of us are aware that at the bedrock there is a lot of love and appreciation there which is currently strained by circumstances, and it's worth holding out and making do until conditions are more favourable.
Ah I don't know. Me and my sister still sometimes joke that when our kids are grown up we'll move in together and be mad old ladies. I actually quite like the idea! Having said that when the kids are more independent I'll probably have the energy to put into my relationship with DP to keep it on the even keel it used to be on when we were childless.
What tht make me wonder is what it would be like if instead of doing that I just literally pleased myself, or even found someone who worked around my wants and ways the way I always have around his.
I wonder if it's me specifically or female conditioning that has made me always inclined to give way to/prioritise the other person/people in my life. I wonder what on earth life would be like if just saying "no that doesn't work for me, I want to do it this way" was something that came naturally to me, instead of always wondering what the other person is thinking/feeling and taking responsibility for that. I think it would be a very different sort of life.