@sun It's usually more complicated.

I knew my wife since 1983 but we got together in a shotgun marriage in 1988.

A friend of mine lost his wife of some 20 years to a disease (cancer IIRC). Then he got married to his high school passion who apparently waited all those years.

My father only dated his 2nd wife for about a year. She's much younger than my mother.

I voted for "1 year" as a stand-in generic.