"This came after many unsuccessful efforts at reconciliation, yet I am still dedicated to keeping the process that lies ahead peaceful for our family," Jenny Sanford said in a statement. The divorce complaint was filed in Charleston County Family Court.
In a statement, the governor blamed himself and said he and Jenny will "work earnestly to be the best mom and dad we can be to four of the finest boys on earth."
"While it is not the course I would have hoped for, or would choose, I want to take full responsibility for the moral failure that led us to this tragic point," he said. "Jenny is a great person, and has been a remarkable wife, mother and first lady. She has been more than gracious these last six months and gone above and beyond in her patience and commitment to put the needs of others in front of her own."
Jenny Sanford's announcement came after a week of wrenching twists, including a decision by a legislative panel Wednesday to turn aside an impeachment push in favor of a formal rebuke for the governor's conduct. He told reporters he still wanted to reconcile with his wife, while she said in a television interview that it was a simple decision to not stand with him as he publicly confessed the affair.
"Certainly his actions hurt me, and they caused consequences for me, but they don't in any way take away my own self-esteem," she told ABC's Barbara Walters. "They reflect poorly on him."
Her divorce complaint did not mention money, property or custody arrangements for the couple's sons.
"The defendant has engaged in a sexual relationship with a woman other than plaintiff," the complaint reads. "Plaintiff has not condoned that relationship and is informed and believes that she is entitled to a divorce ... from the defendant on the grounds of adultery."
As first lady, Jenny Sanford has little official role in state government, but she has been a quiet presence since her husband took office in 2003, often attending morning meetings with his top staff and working on a public health campaign.
Just last week, she welcomed visitors to a holiday open house at the governor's mansion. Mark Sanford arrived about two hours after the event began and gave his wife a quick kiss, but they spent much of the night 10 feet apart, entertaining separate groups.
Jenny Sanford had said after news of the scandal broke in June that she was willing to reconcile with the two-term Republican governor. She weathered the publication of e-mail exchanges between her husband and his lover, Maria Belen Chapur, and an Associated Press interview in which Sanford called Chapur his "soul mate" and admitted "crossing the line" with other women while he was married.
Mark Sanford, 49, disappeared for almost a week in late June to see Chapur leaving his staff, his wife and the rest of the state in the dark about his whereabouts. Initially, his staff told reporters he was hiking on the Appalachian Trail.
Jenny Sanford said she learned about the affair in January when she came across a copy of a letter her husband wrote to Chapur. In the months following, he asked several times to visit the other woman, she said.
"It's one thing to forgive adultery; it's another thing to condone it," she told the AP two days after her husband revealed the affair at a news conference.
"He was told in no uncertain terms not to see her," she said. "I was hoping he was on the Appalachian Trail. But I was not worried about his safety. I was hoping he was doing some real soul searching somewhere and devastated to find out it was Argentina. It's tragic."
Days later, after the governor told AP he was relying on religious faith to help salvage his marriage even though the love of his life was in Argentina, Jenny Sanford said it was up to the people of South Carolina whether they wanted to give their governor a second chance.
"His far more egregious offenses were committed against God, the institutions of marriage and family, our boys and me," she said.
In May, the governor seemed uncertain of what road to take. As the couple was in the midst of a series of religious counseling sessions, he wrote a letter to his spiritual adviser describing himself as emotionally torn.
"The one part where my heart at this point is not where I wish it was is with Jenny," Sanford wrote. She "is a great girl, great mom, great wife and best friend and I am committed to her in a commitment sense, but my heart is just not alive here as it ought to be."
No South Carolina governor has gone through a divorce while in office. The state in 1949 became the last in the nation to allow divorce, said Walter Edgar, a historian at the University of South Carolina.
Born Jennifer Sullivan, the first lady grew up near Chicago. Her grandfather founded the Skil Corp., a power tool manufacturer. She graduated from Georgetown University in 1984 with a degree in finance, then worked for the Wall Street investment banking firm Lazard Freres & Co., where she was a vice president in mergers and acquisitions.
The Sanfords met in New York in the 1980s when Mark Sanford also was working in finance, at Goldman Sachs.
The couple married in 1989 and relocated to South Carolina, where Sanford worked in real estate before serving three terms in Congress. Jenny Sanford managed several of her husband's campaigns. Until revelations of the affair, he had been considered a possible 2012 Republican presidential candidate.
The couple separated two weeks before news of the affair became public. Jenny Sanford and her sons sought refuge at the couple's beachfront home on Sullivans Island while Sanford remained in the state capital of Columbia, occasionally visiting his family.
Unlike some political wives, Jenny Sanford did not stand next to her husband when he revealed the affair with Chapur, whom he met on a trip to Uruguay in 2001.
Here is the text of a statement released Friday by South Carolina first lady Jenny Sanford on filing for divorce from Gov. Mark Sanford months after he publicly confessed an affair with an Argentine woman:
"As so many of us know, the dissolution of any marriage is a sad and painful process. It is also a very personal and private one. Because Mark and I are public figures, we have naturally had less privacy with which to deal with our difficulties than do other couples. Indeed, I know it will soon become known so I choose to release this brief notice that I am now filing for divorce. This came after many unsuccessful efforts at reconciliation, yet I am still dedicated to keeping the process that lies ahead peaceful for our family."
"I remain thankful to so many across this state and nation for their words of encouragement and prayers during this difficult time. Please know the boys and I are doing well and are blessed with the incredible support of friends and family and bolstered by our faith and the unfailing love of our God above."
June 25 - South Carolina reacts to news of affair
June 25 - Jenny Sanford issues statement
June 27 - Wife told Sanford to stop affair
June 30 - Couple went to Bible 'boot camp'
June 30 - Sanford says mistress is soul mate
August 27 - Editorial: Sanford should resign
August 27 - Sanford says he won't quit
October 2 - Sanford lauds Aiken Tech in career center visit
November 24 - Sanford faces 37 charges he broke state ethics laws
December 4 - South Carolina first family faces subdued yule
December 10 - SC Gov. Sanford wants to reconcile with first lady