"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.
A spokesman for her husband, Gov. Mark Sanford, had no immediate comment. The divorce complaint was filed Friday in Charleston County Family Court.
Jenny Sanford's announcement came after a week of wrenching twists in her relationship with the governor. A legislative panel rebuked him for his conduct, he told reporters he still wanted to reconcile with his wife, and 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 four 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."
After news of the scandal broke in June, Jenny Sanford said 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 and an Associated Press interview in which Sanford called the Argentine woman his "soul mate" and admitted "crossing the line" with other women while he was married.
Jenny Sanford had called her husband's behavior "inexcusable" but said she was willing to give him another chance.
Mark Sanford, 49, disappeared for almost a week in late June to see his Argentine lover, Maria Belen 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, her husband 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 during an exclusive interview two days after Sanford's news conference during which he revealed the affair.
"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.
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.
Even afterward, the governor seemed undecided about which road to take.
"I don't want to blow up the kids' lives. I don't want to blow up 20 years that we've invested," he told AP. "But if I'm completely honest, there are still feelings in the way. If we keep pushing it this way, we get those to die off, but they're still there and they're still real."
Jenny Sanford said the couple had been to counseling since she found out about the affair.
"We both indicated a willingness to continue working on the marriage, but there's not room for three people in a marriage," she told the AP. "I've done everything in my power possibly to keep him from going to see her and to really make sure she was off the table, including asking him to leave."