George H. W. Bush and wife Barbara, who were married 73 years and 111 days, hold the record for the longest-married presidential couple

Jimmy and Rosalynn Carter are approaching a record for the longest-married presidential couple, after celebrating their 73rd wedding anniversary Sunday.

The couple is just behind former president George H. W. Bush and his wife Barbara, who were married 73 years and 111 days at the time of the former first lady’s death in 2018.

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In celebration of the Carters’ anniversary, the Jimmy Carter Presidential Library and Carter Center shared black-and-white portraits of Jimmy, 94, and Rosalynn, 91, to honor their love story.

Carter was on break from the Naval Academy in the 1940s when he first asked Rosalynn on a date to the movies. By the next morning, he knew she would someday be his wife, he told the Washington Post.

Image zoom Jimmy and Rosalynn Carter on election night 1976.

Married during the Truman administration, Jimmy, then 21, and Rosalynn, who was 18 at the time, had a secret text-like code to signal their love: “ILYTG.”

“‘I love you the goodest.’ That’s what my mother and daddy used to say back and forth, and I picked it up with Rosa,” Carter previously told PEOPLE in an exclusive 2014 joint-interview with Rosalynn.

The acronym has become a sort of family saying, and even graces a compact Jimmy gave her on their wedding day, now on display at the Jimmy Carter Presidential Library and Museum in Atlanta.

These days, the couple lives life simply in the house they owned before entering the White House’s doors, a Georgia ranch, worth less than $200,000, according to the Washington Post.

The oldest and possibly the most modest of the living former presidents club, Carter takes in the smallest pension, has the least expensive presidential office, and even flies commercial. Yet, he and his wife are always giving back.

Image zoom Jimmy and Rosalynn Carter eating dinner at a friend’s house in their hometown, Plains, Georgia. Matt McClain/The Washington Post/Getty

Despite being in their 90s and some recent health concerns, the pair have continued their work with the Carter Center and still help out with one of their favorite charities, Habitat for Humanity. The former commander-in-chief also famously teaches Sunday school every week.

“They just wear out their staff. They keep one schedule and staff has to switch off in shifts because no one can keep up with them,” their grandson Jason Carter told PEOPLE in 2014.

The couple credits their shared passion for service, as well as their ability to give each other space, for the longevity of their marriage.

In 2014, Carter told PEOPLE they had no intention of stopping: “We still have work to do. I’ll let you know when I slow down.”