How do people with kids do visiting professorships?

Sorry if this is a stupid question, but I often see on people's CVs that they visited at schools hours away from their home institution for either a semester or full year. Many of these people I know to have a spouse and kids. How does this functionally work? Do you force your family to relocate for a short amount of time? That sounds like a nightmare. Or do you just not see them in the week and fly back home every weekend? That also seems tough...