South Carolina Gov. Mark Sanford admitted Wednesday to having an affair with an unidentified Argentinian woman, making him the second prominent Republican in eight days to make such a confession.

“I’ve been unfaithful to my wife,” Sanford said at a news conference in Columbia, S.C. “I’ve spent the last five days of mine crying in Argentina.”

He apologized to his wife, his children, his staff and “people of faith” across the country.

“There are moral absolutes,” he said, referring to “God’s law” as a protection for man against his own wants.

Sanford’s announcement put to rest some, but not all, of the mystery surrounding his nearly weeklong disappearance from the state — a period during which his staff told reporters he was hiking the Appalachian Trail when he was actually in Buenos Aires.

The governor’s confession gives him something else in common with Sen. John Ensign .

The Nevada Republican, who like Sanford appeared to harbor presidential ambitions, told reporters on June 16 that he had a monthslong affair with a woman who was both a campaign aide and a family friend.

Sanford and Ensign are part of a secretive Christian fellowship on Capitol Hill, known as “C Street” for its location, that meets on Tuesday nights, according to sources familiar with the group’s activities.

Sanford said that he had been consulting with the group for months as he and his wife have tried to work through the affair.

Rep. Mike Doyle , D-Pa., a member of the “C Street” group said Wednesday that he would not discuss it.

Sanford resigned his chairmanship of the Republican Governors Association. He was replaced in that post by another potential Republican presidential hopeful, Gov. Haley Barbour of Mississippi.

He did not resign as governor.

In contrast to the way other politicians have handled similar press conferences, Sanford stayed in front of the cameras and answered questions after his announcement.