The former couple — who were married for 25 years — called it quits in 2011 after the Terminator actor came clean to the journalist about his 1996 affair with their housekeeper Mildred Baena that resulted in the birth of their son, Joseph Baena.
In Schwarzenegger's Netflix documentary, Arnold, the former California governor recalled a therapy session where Shriver — with whom he shares daughters Katherine Schwarzenegger, 33, Christina Schwarzenegger, 31, and sons Patrick Schwarzenegger, 29, and Christopher Schwarzenegger, 25, — wanted to know if the 25-year-old was in fact his biological child.
“I thought my heart stopped,” he said of the moment before remembering telling his then-wife, "‘Yes, Maria. Joseph is my son.' She was obviously crushed by that.”
"I have caused enough pain for my family, because of my f***-up," the actor said of the secret relationship with their staffer. "Everyone had to suffer. Maria had to suffer, the kids had to suffer, Joseph, his mother, everyone. I’m going to have to live with that for the rest of my life."
“In the beginning I really didn’t know, but the older he got, the more it became clear to me," he continued. “It was then just a matter of, ‘How do you keep this quiet?.'”
"It was wrong what I did. But I don’t want to make Joseph feel that he is not welcomed in this world — because he is very much welcomed in this world. I love him and he has turned out to be an extraordinary young man," Schwarzenegger admitted.
- Arnold Schwarzenegger Recalls Waking Up During Unplanned Open Heart Surgery: 'It Was a Disaster'
- Rags to Riches: Jim Carrey, Celine Dion, Leonardo DiCaprio and 20 Celebrities Who Started With Nothing
- Arnold Schwarzenegger Admits He Tried to Make 'Terminator 2' More Violent in Order to 'Outdo' Former Rival Sylvester Stallone
Never miss a story — sign up for the OK! newsletter to stay up-to-date on the best of what OK! has to offer. It’s gossip too good to wait for!
Despite the body builder opening up about the painful situation, sources close to Shriver say she will be staying silent. "[Maria] would like to keep what happened in the past behind her and not relive some of the challenges she faced in her marriage," the insider dished.
"She’s in a really good place with Arnold now and they’re able to focus on what matters most to them — their children," the source explained. "She doesn’t live with regrets and chooses to focus her life on positive energy and moving forward."