We started 5 years ago - I've been on call 24/7 ever since. We've now got other people on call too, sure, but as the technical lead, I'm where the buck stops. An average week is in the region of 70-80 hours work.
I have precious little in the way of "life" - I allow myself a few hours off once a week on Thursdays, but apart from that, spend my time glued to my laptop, growing the business.
That said, I see several ways out.
1) This sucker actually works, and we retire. 2) This sucker actually works, and we grow it into a behemoth. 3) Ditto and we sell, and I re-invest the proceeds into my next mad idea.
1 is pretty unlikely. 2&3 are far more likely, which rather reflects the fact that my work is my life, and if you're doing a startup without that attitude, it's going to suffer. A startup is effectively all about selling a "regular" 20/30's for a decade (or two) of brutally hard work, high stress, and attaining financial and inventive freedom.
Sorry, I'm rambling. No coffee yet this morning.