After Caroline Settino met Bruce Johnson in the summer of 2016, they embarked on a whirlwind romance. Mr. Johnson paid for trips to Italy and the Virgin Islands and showered his girlfriend with lavish gifts. A year later, he spent $70,000 on a Tiffany & Co. engagement ring and popped the question at a resort on Cape Cod in Massachusetts.

The fairy tale did not have a happy ending.

Mr. Johnson soon soured on the relationship, broke up with Ms. Settino and sued to get back the ring. The case has slowly made its way through the state courts, which have wrestled with the thorny question of who gets to keep an engagement ring when wedding plans crumble.

On Friday — seven years after the couple’s breakup — the Massachusetts Supreme Judicial Court provided a final answer: “When the planned nuptial does not come to pass, the engagement gift must be returned to the donor,” regardless of which party might be responsible.

For decades, courts in Massachusetts had decided which party should keep a ring by determining which was to blame for the relationship’s demise. The ruling ended that practice, concluding that fault was too difficult to pinpoint — and that broken engagements, however painful, ought not to be cast as failures, anyway.

“Indeed, assessing blame when one party concludes that a proposed marriage would fail is at odds with a principal purpose of an engagement period,” the justices wrote, “to test the permanency of the couple’s wish to marry.”

They also noted the complexity of any such faultfinding mission, given the myriad potential laments of brokenhearted litigants — among them “difficulties with in-laws, hostility of one party’s minor child, pets that cannot get along, untidy habits or religious differences.”