Sometimes, it’s just time to go home
A start-up is a sprint to profitability ... except it's a distance run that tests your endurance.  I did this for a long time and managed a reasonable balance by paying very close attention to my pace.When I was sprinting at full pace, I learned that I could only reasonably expect about 5-6 weeks before I crashed (hard).  I always planned for a much more relaxed pace for a couple months afterwards.On the other hand, if we had a long-term project I could plan about 55-60 hours per week maximum, but I could sustain that pace almost indefinitely while still maintaining a life.If you're doing continuous 80+ hour weeks you need to stop now ... if you don't, your body will fail you and other parts of your life will degrade (relationships).  It's simply not worth it ... a few extra bills in your pocket is not going to compensate for missing life.