Best advice I got from school was "be really careful who you have children with" - and seeing struggles of friends who became single parents with absent or obstructive fathers of the children has confirmed that - though on the other hand if you have children age 20-22, then by your mid-thirties they are old enough for you to go work longer hours and acquire a career.
I've lucked out in many ways - found a chap who is very happy to work 4 days a week and two days at home, thus available for some childcare, but it's affected his career even more than me moving to 3 days - he has had many headhunters trying to poach him, but the firms always insist they want someone working 5 long days a week for around PS130-150k, but working 3 days even for say PS50k would be unacceptable. Does anyone have any idea why most senior managers are so opposed to part-time workers? The dept where DP works has 50 staff, 48 of whom have small children - the pay isn't great for their skills, but the competition won't allow flexibility.
A friend has recently gone back to working full time while her DP does childcare and some self-employed work. She's not sure it's going to work out in the long term, but said no matter what, it is already having the huge benefit of making it clear exactly what is involved in household management and childcare, planning meals, organising child school trips, budgeting holidays etc - so even if she goes back to doing most of that, he will be appreciating it much more! This is why I'm so glad DP worked from home a lot when the kids were babies - he could see I was permanently busy even when the house was a tip!