"When I found out about my husband's infidelity, I worked immediately to first seek reconciliation through forgiveness, and then to work diligently to repair our marriage," she said in a release. "We reached a point where I felt it was important to look my sons in the eyes and maintain my dignity, self-respect, and my basic sense of right and wrong."
But South Carolina's first lady hinted that she was willing to forgive her husband and that "this trial separation was agreed to with the goal of ultimately strengthening our marriage."
Invoking the Bible, she said, "I remain willing to forgive Mark completely for his indiscretions and to welcome him back, in time, if he continues to work toward reconciliation with a true spirit of humility and repentance."
The couple started their careers on Wall Street, where Jenny Sanford was a vice president in mergers and acquisitions at the investment bank Lazard Freres, the Associated Press reports. The couple met in the Hamptons, Long Island, married and headed to South Carolina.
This is the second such scandal to rock the GOP this month. Earlier this month, Sen. John Ensign, R-Nev., admitted to an affair with a campaign staffer and resigned as leader of the Republican Policy Committee.
Almost immediately after Sanford's resignation as chairman of RGA, the organization announced that Mississippi Gov. Haley Barbour will take over as chairman.
South Carolina residents expressed mixed views.
"Here you are cheating. That doesn't stand right with me at all as a woman," Zippora Gregory told ABC News.
"It's happened in politics before and I'm sure it's never going to end," said Camillo Miller.
Sanford recently emerged as an outspoken opponent to President Obama's $787 billion stimulus plan, becoming the only governor to reject the federal stimulus money.
Instead of using the stimulus money to fund projects, Sanford argued that the money instead be used to pay down South Carolina's deficit, an argument rejected by the federal government. He also lost in court when South Carolina's Supreme Court ruled that the governor had to accept the money.
Additionally, the Republican-dominated South Carolina Legislature last week overturned all 10 of Sanford's vetoes on the stimulus.
Sanford was widely seen as eyeing the White House in 2012. In an interview with ABC News two weeks ago, the governor said, "It's not my focus, it's not my aim, it's not my intent," but added "you never say never."
Those ambitions, some say, may be dashed for now.