Barrister and part-time judge Constance Briscoe told Southwark Crown Court yesterday that Vicky Pryce wanted to reveal to the press, after her husband left her for Carina Trimingham, that he infected her with a sexually transmitted disease.
She also claimed Mr Huhne was left with a black eye after Ms Pryce "dragged him through a window" following the collapse of their marriage in 2010.
Ms Briscoe, 56, is on trial accused of lying to police about how she helped Ms Pryce reveal she took speeding points for Mr Huhne.
Answering questions from Patrick Gibbs QC, for the defence, Ms Briscoe said: "She wanted to discuss the fact that Chris had relations with men before they got married, and also wanted to discuss how he had infected her with an STD when he was a European MP, and when she confronted him at the time he said he got it from clean sheets.
"She felt extremely bitter about the marriage break-up and she felt that the reason why the marriage had broken up was because of Chris and, can I say, his sexuality. She believed that the reason why the marriage had broken down was because Chris, her husband, had been engaging in that activity again and that was the real reason for the break-up of her marriage.
"She was cross with Miss Trimingham but she was more furious with Chris because he had conducted a campaign on family values at the time he had that affair with Miss Trimingham.
"Her attitude was that Chris had run off with a man." Ms Briscoe said on one occasion after the split, Ms Pryce attacked him.
The trial continues.