I've seen it where the spouses share a marital home and switch off to the same apartment, alternating weeks at each residence, so there's two, not three places to live.
That only sort of works when both spouses are in agreement they should divorce . If either party is pursuing a relationship, it won’t work.
How does it work for their personal lives? I imagine this works for only so long. Or maybe for the last few years before they are 18. Because you are basically sharing 2 homes with your ex.
