MP Chris Huhne's partner Carina Trimingham has vowed to fight on in her High Court privacy and harassment action.
The PR adviser had sued Associated Newspapers over 65 articles which appeared after her affair with the former secretary of state for energy and climate change became public in June 2010, with Mr Huhne leaving his wife of 26 years.
Associated had fought the case on the basis that there was an important public interest in the story.
Dismissing her claim today, Mr Justice Tugendhat said: "Ms Trimingham was not the purely private figure she claims to be. Her reasonable expectation of privacy has become limited.
"This is mainly by reason of her involvement with Mr Huhne, both professionally, as his press agent, and personally as his secret mistress, in circumstances where he campaigned with a leaflet to the electorate of Eastleigh about how much he valued his family.
"But it is also by reason of what she herself has disclosed in the past.
"Further, she was, as the defendant knew, a journalist who had herself disclosed information about other people for publication in the newspapers and so was a person who ought not reasonably to be expected to be distressed when such information was published about herself."
The judge said he had not found Ms Trimingham to be a good or reliable witness in a number of respects.
"Ms Trimingham has shown little sign of recognising how what she herself has done has given rise to the publicity she finds so unwelcome.
"The difficult situation she found herself in was of her own making.
"One reason why it is objectionable for a sexual relationship to arise between people who are already in a professional or work relationship is that there is then a greatly increased risk of conflicts arising between professional duty and personal interest."
It was this crossing of boundaries which led an editorial executive on the newspaper to consider that Ms Trimingham's role in the story of Mr Huhne was so significant, he added.
"Professionally, it was her job to ensure that Mr Huhne received the best possible publicity, but it was the sexual affair on which she embarked, and which she continued to conduct, with Mr Huhne that gave rise to the scandal."
Ms Trimingham, 44, immediately said she would appeal.
"I am extremely disappointed by this judgment. There is a ray of light, however.
"Thankfully, the court has accepted today that repeated mocking of a person by a national newspaper by reference to their sexual orientation would almost inevitably be so oppressive as to amount to harassment.
"However, the court did not appreciate that when newspapers make repeated irrelevant references to sexuality - particularly in the context of pejorative and stereotypical references to appearance - it amounts to the same type of mocking which the court has confirmed is unacceptable.
"This is confused, and I think wrong. I am very concerned that this judgment may become a blueprint for bullies and bigots."
Her counsel, Matthew Ryder QC, had argued that the Daily Mail had a right to freedom of expression but not to abuse her repeatedly under the guise of exercising that freedom.
The articles referred to the "life and very different loves of the PR girl in Doc Martens" and described her as a "comedy lesbian from central casting".
Antony White QC, for Associated, said Ms Trimingham was not a shrinking violet but a seasoned political journalist.
"She gives as good as she gets. She dishes it out."
A spokesman for Associated Newspapers said later: "This was an important example of the press exercising its right to free speech in relation to matters of significant public interest.
"We are pleased that the court agreed with us and has today dismissed all of Miss Trimingham's complaints.
"The references to Miss Trimingham's sexuality in our coverage were never pejorative, private or in any way homophobic.
"Miss Trimingham chose to level some very serious charges against our journalists in this case. This judgment vindicates both our journalists and their journalism."
Mr Huhne was not a party to the action and did not give evidence or attend the hearing.