Jenny Sanford, wife of South Carolina Gov. Mark Sanford, said her husband looked to leaders of an elite, conservative, Christian group known as "The Fellowship" for guidance during a rough patch in their marriage.
Sanford writes in her memoir, "Staying True," which hit bookstores today, that an adviser from the Fellowship, to whom she gives the fake name "John," counseled her to work through her anger at her husband and to put her marriage and family above all else.
Jenny Sanford does not specify if she was counseled by the well-connected Fellowship Foundation in Washington, but Mark Sanford publicly cited the Fellowship's role in helping him and his family confront his affair during a June 2009 press conference.
His wife's account highlights the extent of the Fellowship's involvement as counsel, and says they even dished out advice on the couple's sex life.
"We went so far as to talk about sex and he told me not to withhold it as punishment as that would make everything worse," she wrote.
Watch Barbara Walters' exclusive interview with Jenny Sanford on "20/20" Friday at 10 p.m. ET
Behind closed doors, the group has been known to offer spiritual guidance for its members, who gather for prayer at a row house on Washington, D.C.'s C Street that is funded by the society.
But the secretive organization has come into the spotlight for its role in the affairs of members Mark Sanford and Sen. John Ensign, R-Nev., where they reportedly became entangled in their members' private lives.
Jeff Sharlet, who says he lived with the Fellowship in 2002 and wrote a book about it called, "The Family: The Secret Fundamentalism at the Heart of American Power," said the group has a record of reaching out to powerful figures during ethics scandals, courting and counseling them in a quest to "infiltrate the world with Jesus."
The male-dominated group preaches subservience, according to Sharlet, and often counsels members' wives to stay in relationships at a high price.
"As Christians are to Christ, so women are to men -- you have to submit to him," Sharlet said. "That's the conservative evangelical world they're in. ... They'll counsel you and help you through this, but your job is to be there for your husband, especially if he's in a position of power."
Efforts to reach the Fellowship were unsucessful.
After Sanford learned of her husband's infidelity, she turned to "John" at the Fellowship again at her husband's recommendation. This time, "John," who Sanford described as someone who "understood men in power well," advised her on "how to handle" her husband.
Rather than seek revenge, Sanford writes, "John" suggested that she focus on forgiveness and let him confront Mark directly with her grievances. Leave the punishment to others, he urged.
"John" served as a crucial ally for Sanford, backing up her decision not to let her husband travel to the Davos Economic Forum in Switzerland or visit his Argentine lover, Maria Belen Chapur, last year.
Cubby Culbertson, a spiritual adviser who counseled Mark Sanford during his time at C Street, accompanied the governor on a trip to New York to see Chapur, Jenny Sanford said.
Sanford refers to Culbertson in her memoir as her husband's babysitter on the trip. But his ultimate goal was to help Mark "regain his moral focus."
Culbertson declined to comment for this article.
After 20 years of marriage, Sanford filed for divorce in December.
The Fellowship also reportedly counseled another of its members, Ensign, who admitted to an affair with Cynthia "Cindy" Hampton, the wife of his former co-chief of staff Doug Hampton, in June 2009.
Doug Hampton spoke with ABC News' Cynthia McFadden in November 2009 about his boss' affair and the cover-up, revealing that he turned to the Fellowship in early 2008 to intervene. At the time, Ensign was a resident at the C Street House.
Hampton said he was not advised by the Fellowship to cover up the affair, but instead to "be cool." He said they felt they needed a more powerful voice to confront Ensign, and reached out to C Street resident and conservative leader Sen. Tom Coburn, R-Okla.
"'We need help. We're not big enough,'" Hampton said, recalling his conversation with the Fellowship. "'[Ensign] is a United States senator and so even though we're friends, we're close, we're brothers in Christ, we need power to confront this: Sen. Tom Coburn, the hit man."
Hampton said that on Valentine's Day 2008, the C Street leadership and Coburn helped him confront Ensign.
"Tom [Coburn] really kind of takes the helm," Hampton recalled. "Oh, he's smoking. He is one upset man. ... And then John kind of breaks down, [saying] 'I made a mistake, I really screwed up.'"
Coburn originally denied he was ever part of brokering a settlement. In a statement to "Nightline" responding to this story, Coburn's spokesman John Hart confirmed that he did offer to help Hampton in the negotiation, but says the conversations were "initiated by Doug, not ... Coburn."
Hampton provided "Nightline" with a letter, which he said the group at C Street forced Ensign to write and send to Cindy, ending the relationship.
"I used you for my own pleasure," Ensign wrote. "God never intended for us to do this."
According to Sharlet, the Fellowship relies heavily on the biblical narrative of King David in its teachings. Despite David's "mixed record" for adultery, he is revered because he was chosen by God for power.
Though the organization has taken steps toward transparency, the Fellowship continues to operate under the radar.