After Mark Sanford lost a GOP House primary to a Trump-backed challenger in 2018, his sons said it was 'the best thing that could have happened' to him

• After Mark Sanford lost his 2018 GOP House primary, his four sons gave him some words of advice.
• "This was the best thing that could ever have happened to you," they told Sanford on election night.
• Sanford recounts the story in his new book, where he opens up about his personal life.

In 2018, conservative Rep. Mark Sanford of South Carolina was locked in a closely-watched Republican primary with Katie Arrington, a challenger who was endorsed by then-President Donald Trump.

Sanford, who served in the House from 1995 to 2001 before occupying the Governor's Mansion from 2003 to 2011 and then winning his old congressional seat back in a 2013 special election, was now part of a Republican Party that was thoroughly dominated by Trump, as he detailed in his newly released book, "Two Roads Diverged."

After criticizing the administration's budget proposal in 2017, Sanford felt the wrath of Trump, who accused the then-congressman of being "unhelpful" in his "campaign to MAGA" and threw his weight behind Arrington.

Sanford eventually lost the June 2018 GOP primary, winning 46.5 percent of the vote to Arrington's 50.6 percent - his first electoral loss since entering politics.

As the longtime lawmaker took in the loss on election night, he remarked on the reaction from his four sons as they hung out at a popular Southern-based fast food restaurant.

"That night, all four of my sons were with me," he wrote. "After the crowd left, we went down to the local Cook Out and stayed up until three that morning, talking of life and politics. It marked a capstone, the end of our years together in the world of politics. They talked of all they had known, given what they had been born into with a dad in Congress, as governor, and then back in Congress."

He added: "That warm June night was marked by stories told and the memories that came with them, laughter, and even an occasional tear on my part as we reminisced on the journey we had taken together. And they all said, 'This was the best thing that could ever have happened to you. You have been miserable over the last two years.' Indeed I had been."

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Sanford's political career hit a major bump in 2009 upon disclosing that he had engaged in an extramarital affair with María Belén Chapur, a woman from Argentina, after he went missing while secretly visiting the country.

He was able to recover politically up until that point, but was struck by the divisiveness that he witnessed while campaigning during his 2018 primary race.

"I had tried to honestly listen to invigorated left-leaning 'Indivisible' and Democratic crowds on one day and Trump-leaning Republicans on the next," Sanford wrote. "It had been a daily tug-of-war. Fox News, where I had once been a darling and where even after losing the governorship had been a paid contributor, would no longer book me because I had been negative toward the president. When I went on CNN, the office the next day would feel the wrath of Republican voters as hate calls were fielded because I had gone on the 'Communist News Network.'"

He added: "In light of those difficulties, I wasn't as upset over my loss as I might have been. And the vote wasn't a blowout either; a few hundred more votes and I would have been in a runoff election, something I had faced twice before and won both times. But Trump's popularity in South Carolina at that time was breathtaking."

Arrington, who lagged in her appeal with Independents, would go on to lose the general election to Democrat Joe Cunningham, a stunning development in the longtime Republican bastion.