I'd like to question the implication that your life is not affected by work as a normal employee of a big company. Sure, it's most probably not going to be as intense as for a start-up, but that's less because of start-up vs big company, but much more about how committed you are to your work in general. I know lots of people working at big companies who have crazy work-hours and whose social life definitely gets affected by that.

Let's face it, if you want to be successful - start-up or not - you'll have to work your butt off.