The Court of Appeal heard the client gave the sex worker a mobile phone as a gift in early 2012.
"He demonstrated the phone's features using his own phone, inadvertently revealing that he had been searching her car's registration number," the court said. At that point, the sex worker, known as "MR" or "Ms M", demanded the man leave at once.
The jilted man seemed to have trouble accepting Ms M's feelings, and repeatedly tried to contact her. He even instructed a private investigator to obtain personal details about the sex worker, including her real name and contact details.
The courts understood the private investigator contacted Ms M's mother and a former landlord to try and get these details.
The sex worker applied for a restraining order against the man under the Harassment Act.
In response to that harassment claim, Mr N brought a civil claim against the woman. He alleged breaches of contract, privacy and confidence.
He also claimed she engaged in "malicious prosecution, abuse of process", defamation and was at fault under the Consumer Guarantees Act.
A district court granted Ms M a five-year restraining order and a judge said the man was "obsessed" with the sex worker. That court also dismissed Mr N's claim as "untenable, frivolous, vexatious and an abuse of process".
Ms M was awarded costs for both these cases.
But the former client lodged contempt proceedings in the High Court against the sex worker and her solicitors.
That contempt proceeding was dismissed too, and costs were again awarded to Ms M and her lawyers.
But the saga continued, escalated, and reached the Court of Appeal, which threw out all the man's applications and told him to pay increased costs to the woman.
Mr N ultimately took his case to the country's highest court. He had four applications for leave to appeal before the Supreme Court - and several other applications.
The former client said the Court of Appeal "denied him natural justice", and was wrong when it denied his request for Ms M and her lawyers to disclose their funding arrangements.
In a decision released yesterday, the Supreme Court rejected all these claims, and the man's suggestions lower courts had shown bias against him in earlier decisions.
The court referred to an earlier district court judge, who said the case was a "sinister use of the Court's processes for the further harassment of [Ms M] through legal procedures".
This week, Supreme Court Justices John McGrath, William Young and Susan Glazebrook said some of Mr N's latest applications appeared "to have the same character" and were "an abuse of process".
All the man's applications were dismissed.
He was told to pay $10,000 costs to the sex worker and $2,500 to her lawyers.
The names of the woman and her former client were suppressed.
