Alexander Hutcheon, 58, of Aberdeen, is accused of racially abusing Steve Agyei, Cherie Blair's former fitness trainer, when he allegedly confronted the couple in a bar in the city.
His wife, Nicola, said she had been in a relationship with Mr Agyei for a year but split up with him a few weeks ago.
The 44-year-old said she had not expected to see her husband when he entered the bar on January 29 and asked her to come home with him after she had stopped their divorce.
Fiscal depute Dorothy Roy asked Mrs Hutcheon: "Why were you with Mr Agyei?" She replied: "Because I still wanted to be."
The mother-of-three said she couldn't really remember whether her husband said anything to Mr Agyei. She said he had been calm during the conversation and she had felt uncomfortable because their 14-year-old son was present..
The court heard that she told the police her husband had called her lover a derogatory name and referred to his clothes being a mess. But she added: "I can't remember any racist remarks being made."
George Mathers, defending, suggested the fitness instructor was out to destroy his client so he could have his wife to himself.
Mrs Hutcheon denied a suggestion he was after her wealth. She said: "I don't think there was any plan to be after my money."
She added: "I can't say that my husband is a racist."
Mr Hutcheon was told there is no case to answer on an assault charge and another of making racist remarks during an argument at their home in Aberdeen.
He still faces a charge of racist abuse. The trial at Aberdeen Sheriff Court continues.