Vicky Pryce said the points swapping remained a bone of contention in her marriage with Chris Huhne, and she would bring it up in rows.
"It really upset me, I thought it was morally repugnant," she told Southwark Crown Court.
Pryce, 60, also told of the moment Huhne, her husband of more than 25 years, told her during half time of a World Cup football match that he had been having a year-and-a-half affair with a woman she knew as a lesbian. She told the court:
He said, 'I have something to tell you. A newspaper has caught me with a mistress and I have to write a note to say that we are separating', or words to that effect. ... I was really shocked.
... And then I asked who it was, and he said Carina (Trimingham). You have to forgive me, I have absolutely nothing against gay people, but I knew Carina as a lesbian. She had come to the house, she was introduced to me as a lesbian always and had a civil partner, a lady. So I said, 'Carina', and I have to say I just couldn't take it seriously. In fact I laughed, because it seemed so preposterous.
More top news
Loyalist paramilitary commander turned supergrass Gary Haggarty has pleaded guilty to 200 terrorist offences, including five murders.
European Commission President Jean-Claude Juncker says the Prime Minister's 'fair and serious' offer to EU nationals doesn't go far enough.
Both the insulation and tiles used in cladding on the Grenfell Tower block also failed safety tests, police said.