Seen as cold and distant, Trierweiler has followed Hollande on international visits and played the role of first lady, but unlike her predecessor Carla Bruni has failed to capture the hearts of the French public.
Trierweiler and Hollande are not married, and his reported affair is shining a new spotlight on the nearly 20,000 euros in taxpayer money spent each month on the first lady's staff and office in the presidential palace.
If Trierweiler's not the president's favorite anymore, the logic goes, why should she get to keep the perks?
Never mind that she's been hospitalized for nearly a week for what her aides call "very strong emotional shock." She reportedly said the news of Hollande's dalliances hit her like a high-speed train.
At a major news conference Tuesday, Hollande confidently brushed off questions about an affair by saying it's private and the French news media and public have so far seemed happy to leave it at that. Commentators on Wednesday praised his unusually statesmanlike demeanor and pontificated on the pro-business twist on his economic policy. Meanwhile, the affair all but disappeared from newscasts.
Compare that to the experience of Bill Clinton.
In the United States, the scandal over his relationship with Monica Lewinsky dominated headlines for months and led to his impeachment for lying to investigators, for which he was aquitted. His wife, Hillary, was generally seen to have come out stronger from the scandal, and her political career flourished.
On Wednesday, many French people seemed ready to move on, just four days after the tabloid report about a late-night rendezvous between Hollande and Gayet around the corner from the president's Elysee Palace.
Hollande's private life "shouldn't be publicly discussed," said Parisian Jean-Paul Lechevalier. "He is a man like others. What is more interesting are his announcements to win back the battle for the economy."
Emmanuel Riviere of the TNS-Sofres polling agency said that attitude is typical.
"The French are not too severe with the idea that political leaders could have liaisons outside marriage, as long as it doesn't impact the course of political action," he said. In fact, he said, some French people "will say that a president who is a (sexual) conqueror, who has the ability to seduce, will be more accepted."
Christine Clerc, a prominent commentator who has written about French presidential couples, criticized Trierweiler for not just fading away quietly.
"There are quite a lot of betrayed women who think that a first lady should face this situation with more dignity," she said. "It's not the first time that we have a president who has affairs with women. It is even part of a certain tradition."
Hollande is the latest in a line of French leaders with complicated private lives. Francois Mitterrand had a secret daughter with his longtime mistress. Valery Giscard d'Estaing reportedly crashed his car en route to a liaison with his lover. Nicolas Sarkozy was the first French president to divorce, date and remarry in office.
Trierweiler's next presidential voyage was meant to be to Washington next month, and Hollande promised Tuesday to make up his mind about his private life before then.
Snide tweeters are suggesting it's time for Trierweiler to go. Leading politician Francois Rebsamen a Socialist like Hollande questioned whether the president's partner needs any role at all. Hollande, when asked about the public money spent on his partner, said it should be made transparent and kept as low as possible.
To be sure, Trierweiler was unpopular to begin with.
She's widely viewed as the reason that Hollande split from longtime partner Segolene Royal. The prominent political couple formally separated just after Royal lost her bid for the presidency in 2007, but it later emerged that Hollande had been having an affair with Trierweiler during the campaign.
After that, the relationship between Hollande's leading women remained tense. Five years later, when Hollande was president and Trierweiler installed as "First Girlfriend," Trierweiler tweeted her support for Royal's rival in a parliamentary election campaign. It went viral, and was seen as a gratuitous dig at Royal.
"I don't have the impression that the French really adopted Valerie," Riviere said. "She never really recovered after the tweet."
During Hollande's push for the presidency in 2012, a lawmaker in Sarkozy's conservative UMP party compared Trierweiler to a Rottweiler.
"Each of these attacks is lower than the last," Trierweiler said at the time.
Her reported rival, actress Julie Gayet, suffered her own setback Wednesday, as France's Culture Ministry denied her a coveted spot at a prestigious French cultural institution. Gayet had been nominated for the jury at the Villa Medici in Rome, but Culture Minister Aurelie Filippetti rejected the nomination. No reason was given.
- AP