I was the exception to that. I worked 14-16 hours per day between my main job and my side gigs for a while and still had to take care of the kids (one mine, one step) at least half the time too. What worked for me was going to sleep at 5 and waking up at 7-8.

My lovely ex-wife, however, slept all night (I had to take breaks from work if the baby needed attention at night) AND took naps during the day along with our baby. I would've liked to sleep more too, but she had a bit of a spending habit, to say the least. We averaged two strollers a month, etc.

Baby is now a toddler and guess who works 50 hours a month and has time and money for the kid and home renovations vs who's unable to pay rent after the divorce. Being the lunatic paid off for me, but not in direct financial gain (anything earned during that era was immediately spent by my ex). Mostly it got me some new connections that appreciate my skills and taught me how much money I could be making per hour if I negotiate well.