The Stormy Daniels affair is the first time Melania Trump hasn't 'stood by her husband'.

First Lady of the United States Melania Trump has a history of standing by her husband, the US President Donald Trump, no matter what his indiscretions are.

Yet following the latest “Stormy Daniels” affair, in which Trump has been accused of paying a former porn star to keep quiet about an affair, the First Lady’s steadfastness has seemingly faltered.

For this reason, all eyes will be on Melania tonight as she appears – if she appears – alongside the president for his State of the Union address at Capitol Hill.

LISTEN: Mia Freedman and Amelia Lester unpack Trump’s affair with Stormy Daniels. Post continues after. 

Traditionally, Melania has aligned herself with Trump regardless of his missteps.

When the 2005 “Access Hollywood” tape of Trump talking about “grabbing women by the pussy” emerged in 2016, Melania defended him on television saying it was “boy talk”.

She stood next to the 71-year-old business-mogul-come-politician when he was accused of sexual misconduct by 19 women in the lead up to the presidential election in 2016.

One woman said he “just started kissing her” mid-conversation, another said she was made to “feel like a piece of meat” at a Miss Universe pageant when Trump, who owned the franchise, walked backstage and into her dressing room.

Trump denied all allegations and counted on his wife of 12 years, Melania, 47, to back him up.

“I believe my husband,” she said on television weeks before the election, The New York Times reports. “I believe my husband. [All these allegations] are organised by the opposition.”

At every point of Trump’s campaign and presidency, Melania has fielded questions and defended the controversial figure. Her spokesperson has issued statements after every scandal, and Melania herself has appeared next to Trump at rallies and speeches and events, showing – if not in words – her solidarity with her husband.

Now, finally perhaps, it seems she’s had enough.

Earlier this month, The Wall Street Journal uncovered a payment of $130,000 ($160,00 AUD) made by a lawyer for President Trump, Michael Cohen, to the account of a former adult film star.

The payment occurred a month before the 2016 election and was part of an agreement that meant Stephanie Clifford (AKA “Stormy Daniels) would not speak publicly about her alleged affair with Trump that took place several years earlier.

Following news of the payment, InTouch published an interview they conducted with Daniels in 2011 in which she admits to a year-long affair with Trump that started in July, 2006. He was recently married to Melania, who had just given birth to Baron Trump in March that year.

According to AP, as reported by The Guardian, the publication did not print the interview with Daniels in 2011 after it received an email from Trump’s lawyers threatening legal action if the story was made public.

Now, it has been made public and Melania is nowhere to be seen.

LISTEN: Mia Freedman and Amelia Lester discuss EVERYTHING happening in the world of Trump this week.

She cancelled her trip to Davos, Switzerland, where she was meant to appear with Trump at the World Economic Forum

She paid an unscheduled visit to the Holocaust Memorial Museum in Washington DC – an unusual show of spontaneity and independence from a First Lady.

And she flew to West Palm Beach, Florida alone where she spent a short trip relaxing at the Mar-a-Lago spa.

Within Daniels' account, there is sex, lots of sex, dinner dates, phone conversations and misleading promises from Trump to land Daniels a job in regular television. Her story was detailed and corroborated by a good friend as well as her ex-husband.

But it was the pay off - more than anything - that reportedly shocked Melania. According to The New York Times, two people close to the couple confirmed she is appalled at the $130,000 bid for Daniel's silence.

Tonight, not for the first time, all eyes will be on Melania's reaction to her husband as he appears publicly after yet another scandal.

But perhaps this time, for the first time, her 'come what may' attitude will show some cracks.