Ironically, Huhne made the pledge in a press interview set up by Carina Trimingham - the very person with whom he broke his pledge just three months later.
The pledge was made in an interview with Chris Semple a top journalist with the premier Hampshire daily newspaper - the Southern Daily Echo in October 2007. The occasion for the interview was part of Huhne's campaign to win the leadership of the Liberal Democrats. Semple conducted a wide-ranging interview about Huhne's claim to be the most suited to lead the Liberal Democrats into the next General Election and a victory that would make Huhne Prime Minister.
The story - with a title that openly mocked Huhne's legendary high self-regard - the headline was: "Is This The Man To Save Our Planet?" - was published on Sunday 21st October 2007.
The writer specifically asked Huhne about the then recent downfall of Huhne's Hampshire colleague, friend and fellow Liberal Democrat MP - Mark Oaten. Just months earlier, Oaten's political career and party leadership aspirations had imploded when the News Of The World (the same paper that recently exposed Huhne's adulterous affair) revealed that Oaten - whose public image was that of a very happily-married family man with 2 kids - had cheated on his wife with someone a bit younger than his wife - who also happened to be a rent boy.
Oaten had also engaged in three-in-a-bed romps and had been on the receiving end of multiple acts of gross humiliation that the newspaper referred to as "a bizarre sex act too revolting to describe." One of his rent boys - a 25 year-old Polish ballet dancer stated delicately: "he was very specific about something special he wanted us to do to him. It's a gross act of humiliation which only a few 'punters' ask for. Quite revolting really".
(this revelation of Oaten's predilection may spoil your appetite)
The act that Oaten begged for was coprophilia in which the rent boys would both empty their bowels on him. In effect using Oaten as a toilet bowl.
The revelations apparently put a slight dent in the image of the Liberal Democrats - particularly in Hampshire.
Given the sensitivity about MPs (especially Liberal Democrats) who promoted themselves as happily-married men with kids - turning out to have a penchant for adulterous sex - especially with lovers who are younger and more butch-looking than their wives - Semple specifically pressed Huhne about his personal life and his marriage.
The story - which is still available online - included a direct quote from Huhne in response to Semple's question.
Mr Huhne also promised not to repeat the situation that developed last time a Hampshire Liberal Democrat was poised to stand for the party's leadership. That situation led to the public humiliation of Winchester's MP Mark Oaten over allegations he had used male prostitutes.
"I'm very comfortable with my life, so nothing like that will emerge," he said.
In fairness to Huhne - in his mind he has not broken his pledge.
Yes he has broken his marital vows - but unlike Mark Oaten, as far as we know he has not engaged in sex with male prostitutes.
While some have unkindly said that Huhne's lesbian girlfriend looks rather like a Polish rent-boy, no one has yet accused her of resembling a ballet dancer.
And there is certainly one crucial difference between the affairs of Oaten and Huhne.
With Oaten, it was he who (at his own request) was crapped on.
With Huhne, it is his wife of 26 years, his five kids and his 80,000 constituents who have been shat on...