COLUMBIA, S.C. — After 20 years of trying and failing to abolish common law marriages in the legislature, South Carolina’s Supreme Court on Wednesday abolished the antiquated practice of allowing couples to claim they’re married without a license if they live together long enough.

The ruling Wednesday doesn’t affect any current common law marriages. But it does require a license for all future legal marriages.

The court used a Charleston County case in which a man and woman began living together in 1989. When they broke up around 2012, the man wanted a divorce and an equal split of their assets.

The justices unanimously ruled against him, noting that while some friends testified that the couple introduced themselves as husband and wife, others testified they didn’t.

There were also confusing signals from medical documents about whether they were married, although they never filed taxes jointly, according to court records.

The couple’s friends didn’t care about their marital status because the social stigma of living together without being married was gone, Justice Kaye Hearn wrote in the court’s opinion.

She said that left courts to determine the mindset of two people who may disagree about whether they were ever married.

“The solemn institution of marriage is thereby reduced to a guessing game with significant ramifications for the individuals involved, as well as any third party dealing with them,” Hearn wrote.

The Supreme Court estimated that fewer than 10 states still recognize common law marriages.

The best way to maintain the institution of marriage is to require people to take an action to show they want to be wed: going to the courthouse and getting a license, the court ruled.

“Our quest to see inside the minds of litigants asserting different motivations and levels of knowledge at varying times must yield to the most reliable measurement of marital intent: a valid marriage certificate,” Hearn wrote.