Francois Hollande's aides convinced a dithering French president that Valerie Trierweiler would make life difficult if she returned to the Elysee Palace, as the former first lady criticised politics as a "world where betrayal pays".
In an interview with 'Paris Match' – the magazine that employs the ex-first lady – Ms Trierweiler said: "When I found out, it was like I'd fallen from a skyscraper".
"Clearly I had heard the rumours but you heard (rumours) about everyone. I hear them about myself too, all of the time. I paid no attention to them."
When he came clean on January 9 about his affair with Julie Gayet, an actress, the pair spent the entire night "talking without sleeping or eating".
But when, the following morning, Ms Trierweiler heard that 'Closer', a gossip magazine, had published photos of Mr Hollande entering a flat near the Elysee shortly after Ms Gayet, she "fainted", she told the magazine.
The following Thursday, Mr Hollande visited her in hospital, where she was recovering from shock and low blood pressure. She told him she was ready to "forgive" him for the affair.
"At a loss", the president asked all the friends he came across that day the same question, "what shall I do?", aides told 'Paris Match'.
The response was: "If she returns to the Elysee, just like any woman who has suffered, she won't let you out of her sight. She'll be checking your diaries. If you aren't prepared to accept these constraints, you should forget her."
Two days later, he told Ms Trierweiler that getting back together would be "difficult", before issuing a terse statement announcing their separation.
Despite the media storm over the break-up, Ms Trierweiler, who has been divorced twice, told 'Paris Match' she was not "undergoing a period of crisis".
"It's not the first break-up in my life," she said. "This one was violent because of the media attention."
Telling the magazine she had no regrets, she said she planned to take up her previous life, "enriched by a new experience".
Speaking separately to another French weekly, 'Le Parisien Magazine', she said she and Mr Hollande had exchanged text messages after his announcement of their break-up because of his concern for her health.
She said the years she worked as a political journalist had not prepared her for the brutality within politics, "a world where betrayal pays".
"At one stage, there's no more life (in a relationship). We didn't experience power in the same way. It broke something. I would have preferred a normal life, with which we might still be together today."
Although she said she is "more sad than angry", Ms Trierweiler said she has not ruled out writing a book about their relationship.
Nathalie Kosciusko-Morizet, candidate for Paris mayor for the centre-right UMP party, said that female voters would find it hard to forget the abrupt manner in which the president announced their split.
"I felt like I was reading a sacking letter rather than a break-up one," she said.
For Jean-Luc Melenchon, the leader of the party of the Left: "His statement was that of an oaf. You just have to read it... me, me, me."
But Harlem Desir, the Socialist Party's first secretary, insisted Mr Hollande was "a very human and very sensitive character".
Ms Gayet has reportedly been keeping a very low profile as friends continue to advise Mr Hollande to remain a "bachelor president". (© Daily Telegraph, London)