As Melania Trump accompanied her husband on his first foreign trip, the public got an uncommon glimpse into the first couple's dynamic.

The First Lady, who remained in New York when President Donald Trump moved to Washington, was more visible than she has been during any other stretch of his presidency. She strode along, usually a pace or two behind, as he greeted dignitaries. She stood over his shoulder as he signed guest books. She ventured out on her own a few times, primarily to meet with women and children. But her foremost job was to accompany the president.

Seeing the Trumps together over the course of their nine-day trip aroused the fascination Americans have with all White House marriages. Do they hold hands? (Not regularly.) Glance at one another lovingly or roll their eyes? (Neither, at least before the cameras.)

On the second leg of their trip, they walked down the tarmac at Israel's Ben Gurion International Airport, and Trump seemed to reach back to take his wife's hand. With a quick flick of the wrist, she seemed to swat it away. The moment, captured on video, went viral.

As they departed Israel the next day, they walked to Air Force One together hand-in-hand as photographers captured the scene. This moment of connection was less commented upon than the apparent brush-off.

For months, Trump's critics have questioned whether the first couple is happily married. Their friends insist that they are.

“I will put my hand in fire and say that they are super, super happy,” said Paolo Zampolli, the Manhattan businessman who introduced the Trumps to each other at a New York Fashion Week party he hosted in 1998 and remains friendly with the couple.

Karen LeFrak, a longtime friend of the Trumps, told a Washington Post reporter that Melania Trump is “enjoying her life and new role... Their relationship is great.”

Melania Trump has described herself as a supportive wife. “We know what our roles are and we are happy with them,” she told Parenting magazine a few years ago. “I think the mistake some people make is they try to change the man they love after they get married. You cannot change a person.”

The President, meanwhile, has repeatedly proclaimed that Melania is doing a wonderful job as First Lady.

“She was always the highest quality that you'll ever find... and I've known her for a long time,” he said at a news conference earlier this year.

He's used blunter terms of praise as well. In a recent conversation on Air Force One, Trump boasted to a supporter that his wife is “Jackie O on steroids.”

The first couple has been married for 12 years and together for 17. The personalities they've presented to the public have typically suggested an opposites-attract dynamic - he is impulsive and decisive, while she is quiet and cautious.

At one point during their foray abroad, they carried themselves like a couple on a double date with other world leaders. An Israeli television station's microphone caught an exchange they shared with Israeli Prime Minister Benjamin Netanyahu and his wife.

“You know in Israel all the people like us - the media hate us but the people love us,” Sara Netanyahu told the Trumps as they met. “Like you.”

“We have a lot in common,” President Trump replied.

In Italy, the president introduced the First Lady to Pope Francis, who shook her hand and asked in Italian: “What do you give him to eat - potica?”

“Potica,” Melania Trump repeated lightheartedly, referring to a Slovenian sweet bread popular in her home country.

If every marriage is a mystery, political marriages are the Twilight Zone. Really, who knows what goes on in the confines of any relationship they are not a part of? So first couples - like celebrities - are subject to endless analysis and interpretation of their every interaction. They are expected to perfect the political performance of marriage.

Barack and Michelle Obama's relationship was a central part of their political story. They both spoke of their family's 6.30pm dinner as a sacred time. They teased each other and held hands in public. She fixed his tie while the cameras snapped photos of them on the North Portico of the White House waiting for guests to arrive for state dinners. He kissed her cheek.

At times, the Obamas seemed to be performing. At a basketball game, they seemed to initially wave away the Kiss Cam when it settled on them - but later called it back and gave a smooch for the crowd.

In 1998, the Clintons were photographed lovingly dancing together, in swimsuits, on a beach vacation. Some political analysts thought the “candid” photo had been staged for the media. Later that same year, amid the sex scandal that engulfed his presidency, Bill and Hillary Clinton made a memorable photo by walking dutifully across the White House lawn together - each holding hands with their then-teenage daughter, Chelsea.

In a moment that made some observers swoon and others cringe, Al Gore planted a full-mouth kiss on wife Tipper at the 2000 Democratic National Convention. The crowd went wild for the show of passion by a man who was perceived as stiff. A decade later, they separated.

Less showy interactions between political couples may be more telling. At the Easter Egg Roll earlier this year, Melania Trump gently nudged her husband as the national anthem was played, to remind him to place his hand over his heart.

She rarely accompanied her husband on the campaign trail, but he referred to her as “his pollster.” Politico reported recently that the first lady continues to watch cable news and report back to her husband how she thinks his communications staff is performing.

Others who have observed the Trumps closely back home, say there is an obvious spark between them.

“When we were together at Mar-a-Lago they looked like they were on a first date,” said Zampolli, referring to a New Year's celebration he attended with the first couple. “They were quite close to each other.”

On another occasion at Mar-a-Lago, prior to the election, Trump interrupted an interview with a Washington Post reporter to call out “Hi, honey!” to Melania, as she passed through in large sunglasses and a bathrobe on her way to the spa. She acknowledged him quickly but kept walking.

In pictures: President Donald Trump on tour Show all 39 1 /39 In pictures: President Donald Trump on tour In pictures: President Donald Trump on tour 20 May 2017 US President Donald Trump and Saudi Arabia's King Salman bin Abdulaziz al-Saud arriving for a reception ahead of a banquet at Murabba Palace in Riyadh Getty Images In pictures: President Donald Trump on tour 20 May 2017 US President Donald Trump, accompanied by First Lady Melania Trump, and Saudi Arabia's King Salman bin Abdulaziz al-Saud being welcomed at Murabba Palace in Riyadh Getty Images In pictures: President Donald Trump on tour 20 May 2017 US President Donald J. Trump with King of Saudi Arabia Salman bin Abdulaziz Al Saud during a welcome ceremony with traditional sword dancers at Murabba Palace, in Riyadh, Saudi Arabia EPA In pictures: President Donald Trump on tour 20 May 2017 King of Saudi Arabia Salman bin Abdulaziz Al Saud with US President Donald J. Trump and wife Melania during a welcome ceremony at Murabba Palace, in Riyadh, Saudi Arabia EPA In pictures: President Donald Trump on tour 20 May 2017 US President Donald Trump adjusts the Collar of Abdulaziz Al Saud Medal, after it was bestowed upon him by Saudi Arabia's King Salman bin Abdulaziz Al Saud at the Royal Court in Riyadh, Saudi Arabia Reuters In pictures: President Donald Trump on tour 20 May 2017 Saudi Arabia's King Salman bin Abdulaziz Al Saud presents U.S. President Donald Trump with the Collar of Abdulaziz Al Saud Medal at the Royal Court in Riyadh, Saudi Arabia Reuters In pictures: President Donald Trump on tour 21 May 2017 Palestinians print posters depicting US President Donald Trump in preparations for his planned visit, in the West Bank town of Bethlehem Reuters In pictures: President Donald Trump on tour 21 May 2017 US President Donald Trump accompanied by first lady Melania Trump, his daughter Ivanka Trump and her husband White House senior advisor Jared Kushner, before delivering his remarks to the Arab Islamic American Summit in Riyadh, Saudi Arabia Reuters In pictures: President Donald Trump on tour 21 May 2017 US President Donald Trump looks on as U.S. Secretary of State Rex Tillerson and Saudi Arabia's Crown Prince Muhammad bin Nayef exchange a memorandum of understanding Reuters In pictures: President Donald Trump on tour 21 May 2017 First Lady Melania Trump shares a laugh with a child during a visit to the American International School in the Saudi capital Riyadh Getty Images In pictures: President Donald Trump on tour 21 May 2017 US President Donald Trump holds a bilateral meeting with Bahrain's King Hamad bin Isa Al Khalifa AP In pictures: President Donald Trump on tour 22 May 2017 Israeli soldiers rest during preparations ahead of President Trump's landing in Tel Aviv, Israel Getty Images In pictures: President Donald Trump on tour 22 May 2017 First Lady Melania Trump makes her way to board Air Force One in Riyadh as she heads with her husband the US President to Israel Getty Images In pictures: President Donald Trump on tour 22 May 2017 US President Donald Trump and first lady Melania Trump board Air Force One for Israel, the next stop in Trump's international tour, at King Khalid International Airport AP In pictures: President Donald Trump on tour 22 May 2017 Israeli soldiers wait for the arrival ceremony of US President Donald Trump at Ben Gurion airport near Tel Aviv, Israel AP In pictures: President Donald Trump on tour 22 May 2017 US President Donald Trump and first lady Melania Trump arrive aboard Air Force One at Ben Gurion International Airport in Lod near Tel Aviv, Israel Reuters In pictures: President Donald Trump on tour 22 May 2017 US President Donald Trump and first lady Melania Trump disembark Air Force One on arrival at Ben Gurion International Airport AP In pictures: President Donald Trump on tour 22 May 2017 US President Donald J. Trump and his wife, US First Lady Melania Trump are welcomed by Israeli Prime Minister Benjamin Netanyahu upon arrival at Ben Gurion Airport, in Lod outside Tel Aviv, Israel EPA In pictures: President Donald Trump on tour 22 May 2017 US President Donald Trump and Israeli Prime Minister Benjamin Netanyahu sit during welcome ceremony in Tel Aviv AP In pictures: President Donald Trump on tour 22 May 2017 US First Lady Melania Trump chats wife Sara Netanyahu as US President Donald Trump chats to Israel's Prime Minister Benjamin Netanyahu during a welcoming ceremony to welcome Trump at Ben Gurion International Airport Reuters In pictures: President Donald Trump on tour 22 May 2017 US President Donald Trump delivers a speech upon his arrival at Ben Gurion International Airport in Tel Aviv Getty Images In pictures: President Donald Trump on tour 22 May 2017 US President Donald Trump gestures during a press conference with Israel's President at the President's Residence in Jerusalem Getty Images In pictures: President Donald Trump on tour 22 May 2017 US President Donald Trump watches as First Lady Melania Trump signs the guest book at the President's Residence in Jerusalem Getty Images In pictures: President Donald Trump on tour 22 May 2017 US President Donald Trump walks with first lady Melania Trump in Jerusalem's Old City Reuters In pictures: President Donald Trump on tour 22 May 2017 US President Donald Trump visits the Western Wall, the holiest site where Jews can pray, in Jerusalems Old City Getty Images In pictures: President Donald Trump on tour 22 May 2017 US President Donald Trump stands next to Rabbi Shmuel Rabinowitz at the plaza in front of the Western Wall, Judaism's holiest prayer site, in Jerusalem's Old City Reuters In pictures: President Donald Trump on tour 22 May 2017 US Secretary of State Rex Tillerson and White House senior advisor Jared Kushner leave notes at the Western Wall in Jerusalem Reuters In pictures: President Donald Trump on tour 22 May 2017 US First Lady Melania Trump touches the Western Wall, Judaism's holiest prayer site, in Jerusalem's Old City EPA In pictures: President Donald Trump on tour 22 May 2017 Ivanka Trump, assistant and daughter of US President Donald J. Trump, touches the Western Wall, Judaism's holiest prayer site, in Jerusalem's Old City EPA In pictures: President Donald Trump on tour 22 May 2017 President Donald Trump visits the Western Wall AP In pictures: President Donald Trump on tour 24 May 2017 US President Donald J. Trump arrives in a vehicle to Saint Damaso's Court for a private audience with Pope Francis in Vatican City EPA In pictures: President Donald Trump on tour 24 May 2017 Pope Francis walks past Ivanka Trump and First Lady Melania Trump on the occasion of the private audience with President Donald Trump, at the Vatican AP In pictures: President Donald Trump on tour 24 May 2017 Pope Francis exchanges gifts with US President Donald Trump during a private audience at the Vatican Getty Images In pictures: President Donald Trump on tour 24 May 2017 Pope Francis meets US President Donald Trump and his wife Melania during a private audience at the Vatican Reuters In pictures: President Donald Trump on tour 24 May 2017 Pope Francis with US President Donald J. Trump EPA In pictures: President Donald Trump on tour 24 May 2017 Pope Francis gets into is car after meeting with US President Donald Trump AP In pictures: President Donald Trump on tour 24 May 2017 President Donald Trump and his wife Melania look at the frescoed ceilings during their visit to the Sistine Chapel at the Vatican L'Osservatore Romano/Pool Photo via AP In pictures: President Donald Trump on tour 24 May 2017 US President Donald Trump security vehicles are seen in front of Air Force One before take off from Leonardo da Vinci-Fiumicino Airport in Rome, Italy Reuters In pictures: President Donald Trump on tour 24 May 2017 US President Donald Trump and First Lady Melania Trump wave to reporters before boarding the Air Force One to Brussels, at the end of a 2-day visit to Italy including a meeting with Pope Francis at the Vatican, at Rome's Fiumicino international airport AP

The Trumps will wrap up their tour abroad on Saturday, and this summer Melania Trump is expected to move to Washington, where the media glare and public interest in their marriage could intensify.

“She is very strong, and he's very strong, but of course it is not pleasant,” Zampolli said.