Elizabeth Edwards stayed with her philandering husband because she has terminal cancer and was concerned about the impact of a public break-up on their children, her closest friend has told a US magazine A week after John Edwards admitted that he had lied to the press by denying the affair, much of the US media remains obsessed with the scandal engulfing the former Democratic presidential candidate.

Mrs Edwards is thought to have authorised her best friend to explain how she felt when her husband confessed his relationship with Rielle Hunter, a documentary film-maker.

“No one should assume it was easy,” said Hargrave McElroy, who explained how Mrs Edwards experienced “excruciating anguish” over her decision to stand by him throughout the campaign. “She had to make a choice: Do I kick him out or do we have a 30-year marriage that can be rebuilt? She couldn’t say, ‘Maybe we’ll work through this, or maybe we should separate for two years.’ [The cancer] forced her to choose whether to move forward.”

People magazine’s story yesterday also featured an interview with Mrs Edwards’s younger brother, Jay Anania, who said that “the uncertainty of her own mortality” and the feelings of her children had been a major factor in persuading her to forgive her husband.

There were further claims that her husband “told the truth slowly” in informing her about the affair only after the official launch of the presidential campaign in December 2006. In March last year, Mrs Edwards disclosed that her breast cancer had returned and was incurable.

Ms Hunter, 44, has a five-month old daughter whose paternity is the subject of intense speculation. Mr Edwards denies being the father, insists the affair ended long before his lover become pregnant and has offered to take a DNA test.

There have been a series of newspaper reports casting doubt on Mr Edwards’s claims about when the affair finished. A long-standing friend of Mr Edwards told The Times this week: “This is not the end of the story. I think it is only just beginning.”

Until last week Mr Edwards could have expected a prime-time speaking slot at the Democratic convention in Denver at the end of the month. Now, however, neither he nor his wife are expected to be seen within a hundred miles of Colorado.

Hillary Clinton, whose supporters continue to resent her defeat in the primaries, has also managed to cast a pall over Barack Obama’s preparations for the convention.

The two issued a joint statement announcing that there would be a roll-call of votes at the convention in Denver, allowing Mrs Clinton’s supporters one last chance to cheer their champion just 24 hours after she makes a big speech to delegates.

Times Recommends

• 'New York has lost its edge'
• Copenhagen will fail – and quite right too
• More than 17,000 new underwater species found