Only possible because my wife saved up a bunch of money while I was working. Now we're burning through that, I'm updating my portfolio, blowing the dust and cobwebs off several startup ideas I had shelved for so long. No income yet; I'm going to start aggressively looking for consulting work as soon as the portfolio is up. I've had a couple "fell in my lap" job leads from friends but none are in my area and I can't move right now.
I'm hoping to hit some kind of rhythm where I'm able to stay just afloat with a part-time contract work, and the rest of my time I can spend time 1. with the wife and 2. exploring my experimental software ideas.
My mantra and rationale remains unchanged: even if I fail at this little adventure and go broke and have to panic and reorganize my life, that in itself will be a lot more fulfilling and exciting than the burnt-out, depressed place I was in at my former job.
I've heard that when skydiving, once you reach terminal velocity it's becomes less frightening. So it doesn't feel too bad right now. But I'm entirely aware that the ground is quite hard and only a few thousand feet, er, dollars away.
Best of luck to you!