Last month, Mr Woodhead survived calls for his resignation following the revelation he had had a relationship with Amanda Johnston, a pupil at Gordano School near Bristol. Both claimed they only became intimate after she left the school.
But in an article in today's Mail on Sunday, Cathy Woodhead claims her former husband confessed to her about the affair while he was still on the staff of the school.
Mr Woodhead, who spoke last night to the Totnes Conservative Association, said: "I am on the public record and so is Amanda Johnston. My ex-wife can say whatever she likes, I have got nothing to say."
Mrs Woodhead further claims that her then husband proposed an extraordinary solution - a menage a trois with his wife and girlfriend living under the same roof. The couple's daughter, Tammy, was 15 months old at the time and Mrs Woodhead claims: "Chris said I should consider myself lucky I would have both him and Amanda to look after Tammy." Soon after, the couple separated. The affair took place 23 years ago.
Mr Woodhead embarrassed his boss, David Blunkett, earlier this year by telling student teachers at Exeter University that relationships between teachers and pupils could be "experiential and educative".
He subsequently apologised for his remarks and Mr Blunkett threw his weight behind him despite calls for his sacking.
At the time, Mr Woodhead said: "There is an enormous difference between having a relationship after a teacher has stopped teaching a pupil and having an affair with that pupil whilst the teaching relationship is going on."
Mrs Woodhead said his denials are untrue. "I have lived with the knowledge that Chris had a sexual relationship with a pupil at the school where he taught. I learned that for certain in 1976, when he told me he was having an affair with a girl named Amanda Johnston, a sixth-former at Gordano school where he was head of the English department."
A spokesman for Mr Blunkett refused to comment last night.
Mr Woodhead has infuriated teachers with his back-to-basics views. He has won admirers and enemies in equal numbers with his claims that up to 15,000 teachers are incompetent.Reuse content