I, too, had a really difficult time making this decision. Ultimately, I decided to leave my job -- but more because I felt I was totally burnt rather than I felt my children or family were suffering because I was working.
Things I found about myself when I left my corporate job:
- It took me a while (like, over a year) to stop defining myself by my outside job. I had a hard time introducing myself without adding "...and I recently retired from XYZ company as -----."
- I had used the parameters of my job to help keep me on schedule, organized and focused at home. It took me a while to define a schedule and keep things moving forward at home -- and I could still improve at that, years later. I definitely benefitted from the externally imposed structure.
- I really enjoyed using the skills I acquired at my job in volunteer work in my daughters' school and in my community. And sometimes it still makes me crazy that SOME people/moms who never worked outside the home just don't get how to manage a project without it being about friends and personalities. I mean, we can and should certainly enjoy each others' company & have fun, but please can we get some work done without gossiping about whoever isn't in the room?
I got a funny (and unexpected and disappointing) initial reaction from my kids (who are as change-averse as I am). They were really upset that our nanny wouldn't be there anymore! It took a while, but they came to see that Mom could be as good to have around as the nanny. Guess all my worries about them suffering because I wasn't always home were for naught!
Still, for me, it was a good decision. Good luck making yours. It's not as much a "no brainer" as others think, and it doesn't mean you don't love your family because you also enjoy your work outside. Each family works through these things in the way that works best for them.