What is the older English word for Living Apart Together (Marriage)?

When married couples choose to maintain separate homes while staying together, it is called a Living Apart Together (LAT) relationship. This is a modern term from the 1970s. I am sure there is an older term in English for this arrangement, but Google is of no help. Help?

Key Aspects of LAT Marriages
Intentionally separate: Partners choose to live apart by design rather than due to a temporary crisis or an impending divorce.

Independent spaces: Each person keeps their own home, which can range from separate apartments in the same building to houses in different cities.

Maintained connection: The couple stays emotionally, romantically, and legally committed to one another.

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