Thanks for coming back, that does make sense.
I've been ft with 3 DC's - currently on mat leave with #4 and due to return full time also.
If I won the lottery, I'd be a SAHM in a flash - I love being with the kids, and there's plenty to do as they get older with school, plus holidays, seeing family etc. However I'm the main earner, and it has been good for me to go back as 3 years ago my DH had unexpected health issues that meant he had to leave his previous job for 6 months and then go part time for 6 more - if I'd been earning less, we would have been in real trouble. In my field pt roles are rare, though I do work a day a week from home and often leave 'early' at 5pm and pick up again once kids are asleep.
With one DC in nursery, two people full time is totally workable, but I do think it can be hard on a young baby. The key is making sure you are both able to take days off when the child inevitably gets sick, so one person is not taking all the hits.
It gets harder with school - there are school holidays to manage, inset days, sports days, concerts, before and after school care can be tricky to guarantee and navigate, and a reception child, for example, is often knackered by 3.30 and really wants to be home.
The other challenge is home and life admin. If you don't have a cleaner then you have to spend more of your very limited free time on the house.
My perfect idea would be both of us 3-4 days a week, so DC's are in external care 3 days max. However right now we'll both be 5 days - but we will have a nanny, which helps a lot, as it gives more continuity of care and a chance for them to be home more, and also a cleaner who irons, so that when we are home we can maximise our time with children.
So in summary - yes it's doable, 2 people working full time office hours is hard and not really ideal, the best fix is to pay for as much help as you can, and negotiate as much flexibility as you can for BOTH partners, not just the mother. One important thing is also if you're planning more DC - it can be helpful to keep your career going when they're young, it's hard but means that by the time they're at school you've proved yourself enough that you can easily work from home, or start and leave early one day a week to do dropoff, or pop out in the middle of the day for a concert. Some of my friends were home with small DCs then wanted to go back once all were at school, but it's hard to have a long CV gap, and all needed to take big pay cuts and then had less flexibility once they got a job.