'I fell deeply in love': Mark Sanford says he 'caused incalculable pain' in handling of extramarital affair with María Belén Chapur in Argentina

• In his new book, Mark Sanford lamented how he handled an extramarital affair that captivated the US.
• Sanford quietly flew to Argentina to see his then-lover in 2009, giving an excuse for his absence.
• He faced calls to step down from his post but ended up serving out his term.

In 2009, Republican Gov. Mark Sanford of South Carolina was nearing the end of his second term in office and by all public accounts had a successful political career and family life.

But despite being married, Sanford had fallen "deeply in love" with María Belén Chapur, an Argentine journalist he had known for several years. Once his wife, Jenny, discovered a file of letters between her husband and Chapur in December 2008, things became increasingly difficult for the married couple, as Sanford detailed in his newly released book, "Two Roads Diverged."

"Jenny's discovery eventually led us to marriage counseling, and amid ... the responsibilities of raising four sons, we did the best we could to sort through what was tough at a private level and what at any given moment might morph into an even more difficult public drama," he wrote. "By May 2009, Jenny had asked for a trial separation."

He emphasized: "One month later, I chose a path that caused incalculable pain for all of us."

Sanford went on to describe how in June 2009, he took a flight to Buenos Aires to see Chapur, while instructing his staff to tell his wife that he was "hiking on the Appalachian Trail" if she tried to reach him.

"I had concocted the strangest of plans in a desperate effort to get my life back," he wrote. "Jenny wanted a quick and timely resolution to the relationship, and if she didn't get it, she would be taking my news public in early July. She had never been one to bluff. I told her that the counselors we met with had all said that if one took the actions of love, in time good things would follow."

He added: "I was committed to the actions, but we needed time. We hadn't gotten into this problem overnight, and we wouldn't get out of it overnight. She was, however, fixed on a quick resolution."

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Sanford wrote that he thought he'd be able to conceal the trip to Argentina.

"I thought I could go to Argentina over a long weekend and get it all figured out," he wrote. "The open window was narrow. It had to fall between the end of the legislative session and Jenny's deadline of early July. But my plan proved to be as poorly constructed as it was desperate."

State legislative leaders, and then Jenny, told the press they hadn't heard from Sanford, and the former governor described being ready to face a huge blowback in South Carolina after being contacted in Argentina.

"My office called me in Argentina later that night," he wrote. "I felt as though I had gotten word of my impending execution. I just didn't know its form. I felt as though life as I had known it was over. Both were true."

Upon returning to South Carolina the next day, Sanford held a press conference in which he confessed to the affair.

While there were five separate investigations and calls for Sanford to resign, he eventually paid out $74,000 in a settlement with an ethics committee and served out the rest of his term, which ended in 2011.

He was succeeded in office by the Republican Nikki Haley.

Sanford, who later became engaged to Chapur before that relationship eventually ended, remains remorseful of his actions during that period.

"I suppose I never will completely finish apologizing, but what I tried to do in those first eighteen minutes of my press conference, I repeated often during the remaining eighteen months of my time in office," he wrote.

"After a little more time, people began telling me, 'It's time to stop with the apology tour.' But there is something right about owning your past, of saying up front you were wrong and are sorry for what you did."