They are not talking about how they schedule and manage the family life. They are talking about desperately needing some time away from the family. Which is normal and healthy (depending on whether you discuss it and make time for yourself, or whether you escape trough alcohol and ridiculous amounts of time at work).
Also just being able to work without distraction. It's very hard to explain to young children that they cannot disturb their parents for several hours and many people won't have a spare room just to work.
