I reckon you should spend unstructured time with your kids. It wouldn't kill you to be a little maternalistic.
Structured time is when the children have a particular timetable, for example going to an after-school club. A family might also structure homework time. "You do homework from 5:30 to 6:30..."
Unstructured time is when the children don't have anything particular to do, and can play, relax, watch tv etc. The suggestion is that the mother should spend more time relaxing and playing with her children.
This is quite easy to check using a web-search. You can sometimes use google (or another search engine) as a way of looking for definitions and examples.