When kids were added to the family, it actually improved my life. I actually had motivation then for making money—and making time.
Now, empty nested, I can see that I was both rudderless and identity-less before the kids. I'm wandering now (and retired) trying to find a replacement identity.
I'm still a father of course (and husband) but with less input and less to do. In fact I feel inclined to step back and let the girls have their lives now. So I road-trip, come up with projects to keep me busy, try to be an "educator".
People underestimate how quickly you burn out when you're completely on your own. It's the people around you that give you purpose and motivation.