Arnold Schwarzenegger has revealed his wife confronted him about his affair during a therapy session.

The Terminator actor speaks about his infidelity in his new memoir Total Recall: My Unbelievably True Life Story. In the tome, Arnold says his estranged wife Maria Shriver had long suspected he was unfaithful.

"The minute we sat down, the therapist turned to me and said, Maria wanted to come here today and to ask about a child - whether you fathered a child with your housekeeper Mildred [Baena]," he writes. "I told the therapist, It's true."

The counselling session took place a day after he left his role as Governor of California in January 2011.

Arnold reveals his covert relationship with Mildred happened while he was working on Batman & Robin and his family were away on holiday in 1996.

He also admits that he gave Maria "lame" reasons about why he had previously denied the affair, including embarrassment and not wanting to tell her family the famous Kennedy clan.

"Instead of doing the right thing, I'd just put the truth in a mental compartment and locked it up where I didn't deal with it every day," he says in the book. "I blocked out the fact that as a husband and father, as a man with a family and wife, I was letting people down."

Arnold still hopes Maria will give their relationship another chance.

"You can call this denial but it's the way my mind works," he explained.