(CNN) Twenty-six thousand seven hundred and sixty-six days -- and counting.

That's more than 73 years. And that's how long former President Jimmy Carter and his wife, Rosalynn, have been married -- making them the longest married presidential couple.

The Carter Center celebrated the milestone Thursday when the couple bested the record held by the late George H.W. Bush and Barbara Bush

And to think it might have turned out differently.

When Jimmy Carter first proposed, Rosalynn Smith -- as she was known then -- rejected him. Why? She had made a promise to her dying father she'd finish college first.

As she recounted in her memoir, "First Lady from Plains," the pair grew up three years and three miles apart.

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