Jenny Sanford filed for divorce on Friday from her husband, Gov. Mark Sanford of South Carolina, who confessed in June to an affair with a woman in Argentina.

“As so many of us know, the dissolution of any marriage is a sad and painful process,” Ms. Sanford said in a statement. “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.”

The Sanfords have been separated since shortly after he admitted the affair in a teary-eyed news conference. Although Ms. Sanford has been living at the family’s beach house on Sullivan’s Island, S.C., with her four sons, the Sanfords have said publicly that they hoped to salvage the marriage. As recently as Thursday, Mr. Sanford told reporters that he wanted to remain married.

But that proved untenable, Ms. Sanford said in the statement. “This came after many unsuccessful efforts at reconciliation,” she said, “yet I am still dedicated to keeping the process that lies ahead peaceful for our family.”