Chiming in to agree with the PP.
When I was working FT, I was bringing home about 40% of our income, so it didn't compare to your finances. Daycare costs were, depending on the season, up to 2/3 what I made. My dh travels for his FT job, we have a small farm and two children, and I was that person--I was the pick up, drop off, breakfast-lunch-dinner maker, livestock feeder/waterer, homework supervisor, bath-giver, snow shoveler, garden waterer...I was wiped all the time and making up the work time on weekends, too. So, I downsized my job to PT. It was a little better, but then we started the home projects--renovations, more gardens, etc. I could simply not do it all anymore.
I quit my job. And I cried over it. Because I enjoyed the work, the colleagues, the clients, the satisfaction, and bringing a paycheck felt really good. With both kids getting to school age, I told myself to just hold on, hang in there...but I couldn't. I was at the end of my rope.
It's been a great 4 months since. We have not suffered financially, and we have been lucky that dh still has his job. But this week, my job came back to me. I actually got a new offer from my same employer. It's the same work, but a new position. I'm a flex worker now. I don't need to report to the office. I likely won't have regular hours, but rather will fill gaps as needed. I could work a couple weeks and then have a week or two (or 6?) without work. I know it isn't the same as a family-supporting career, but I wanted to share my incredibly fortunate, positive experience. I feel so blessed.
I don't know how it is going to work out, or how much I will need to struggle to defend my boundaries, but I am going to give it a shot. I still have a dh who travels, a farm, two school-agers, and two other passions that I refuse to give up (running and fiction writing), so it will always be a careful balance. But I have this opportunity and would regret not trying.