CHARLESTON, S.C. -- South Carolina first lady Jenny Sanford says the final blow to her marriage came with the publication of racy e-mails between Gov. Mark Sanford and his mistress.
She also tells ABC's Barbara Walters in an interview airing Friday on "20/20" that she made a "leap of faith" marrying Sanford more than 20 years ago because he insisted on removing a clause promising to be faithful from their wedding vows.
The show released excerpts of Sanford's interview with Walters, which coincides with publication of her memoir, "Staying True."
In the interview, Jenny Sanford says the e-mails where her husband talked about his lover's body parts were not something anyone would want their children to read on the Internet. They were published last year by The State newspaper in Columbia, appearing online the same day the governor returned from a five-day absence - his staff told reporters he was hiking the Appalachian Trail - to admit an affair with an Argentine woman.
Mark Sanford revealed the affair with Maria Belen Chapur in a tearful news conference at the Statehouse.
One e-mail from the governor read: "I could digress and say that you have the ability to give magnificent gentle kisses, or that I love your tan lines or that I love the curve of your hips, the erotic beauty of you holding yourself (or two magnificent parts of yourself) in the faded glow of the night's light - but hey, that would be going into sexual details."
Jenny Sanford tells Walters her children were devastated.
"It just ripped me up, to see them reading these e-mails, to see them have to grow up so fast," she says.
Jenny Sanford has filed for a divorce that is to be finalized later this month. Last summer she moved out of the governor's mansion in Columbia and now lives with the couple's four sons at the family's beachfront home on Sullivans Island.
Removing the vow of faithfulness from their marriage ceremony "bothered me to some extent, but ... we were very young, we were in love," Sanford says. "I questioned it, but I got past it."
She did not stand by her man when he announced the details of the affair to a waiting world but tells Walters it was a terrible thing to watch.
"It was awful for me to watch my husband come back and pine about his 'soul mate' and days spent crying in Argentina," Jenny Sanford says. "It was awful to think that the world now, you know, was watching this about us and our marriage. It was awful from the political standpoint because he really should've, should've stopped talking at a certain point."
The governor's office had no comment Wednesday.
Mark Sanford, in Myrtle Beach for a tourism conference, told The Sun News newspaper on Tuesday that he had not read his wife's book.
"I know anything Jenny does, she does well, so I look forward to reading it along with everybody else," he said.
Jenny Sanford says she is ready to get on with her life.
"I'm looking forward to whatever comes next," she says in the interview, adding that if she pondered for the rest of her life, she will probably never know what went wrong with her marriage.
"I would say I have acted honorably in our marriage and I've been the best wife I can be," she says.