Arnold Schwarzenegger says his lifelong penchant for secrecy and ability to put his emotions "on deep freeze" led him to keep many secrets from his wife Maria Shriver.
This eventually caused the break-up of their marriage, says the Terminator star, who was forced to admit fathering a child with the family's housekeeper.
Throughout their 25-year marriage, Arnie confessed he did not want to tell Maria, a member of the Kennedy clan, about crucial life decisions because he feared she would overreact and tell her well-connected family and friends.
In his new autobiography, Total Recall: My Unbelievably True Life Story, and in an interview on the TV news magazine 60 Minutes, the former California governor acknowledges that his inability to be honest with people had hurt those closest to him.
"That's the way I handle things," the actor told reporter Lesley Stahl on 60 Minutes.
The star, 65, traces his detachment to his bodybuilding days, where he says emotions make athletes lose.
But Arnold's biggest secret, the child he had with the family's housekeeper, became tabloid news last year after he left office.
Maria confronted her husband during a counselling session in January 2011 and he finally acknowledged the boy, Joseph, was his.
He said he never even had a conversation with the housekeeper, Mildred Baena, about the son.
Instead, after he began noticing the boy's strong resemblance to him, around the age of eight, he just began giving Mildred extra money.
He declined to say whether he has a relationship with the child, who is now about 15, and he said he did not want to go into any more details about his relationship with Guatemala-born Mildred because he had already caused Maria and their four children enough pain.