My first had major medical issues (for her first 3-4 years) that necessitated close supervision after a 3-month stay in the NICU. She had PT, OT, speech therapy, and feeding therapy every week, appointments with cardiology and pulmonology, gastroenterology, regular post-operation and post-NICU visits, and the normal doctor appointments.
She took a lot of work, and severely limited our options for going out, due to a feeding schedule (while trying to limit projectile vomiting – and I do mean vomiting, hard and loudly, not just “spitting up” – to 2 times a day, when possible) that allowed practically nothing. Still, we managed to have downtime, where we could just relax and unwind. It’s how we stayed sane.
Given the circumstances, a second child really changed very little, in terms of work required. We still found time for ourselves.
Admittedly, it would have been impossible (or extremely cost-ineffective) for me to have a job at that point, but my daughter was a full-time job and then some. I realize that this probably negates everything I’ve said to most in this thread, but still.