For some, infidelity is one of those discreet topics discussed in hush tones between intimates, but not so for Savannah-based memoirist Harrison Scott Key. Winner of the Thurber Prize for American Humor for his 2015 debut “The World’s Largest Man,” he took the opposite approach when his wife — a homeschooled preacher’s daughter and the mother of three — confessed to falling in love with another man.

First, he pretty much told everyone he knew, including his wife’s family, and then he wrote a book about it: “How to Stay Married: The Most Insane Love Story Ever Told” (Avid Reader Press, $27.99).

Key’s gift for looking at the world “through funny glasses” proves to be his saving grace as he negotiates his way through the life-shattering event. It also makes the experience of reading about his trauma wildly entertaining.

Charting the trajectory of the couple’s relationship, he recalls their early, heady days of romance when “we were spouting desperate I love yous like toddlers who’d just learned how to say chicken nuggets.” By the time they hit middle age, he ponders the moment his wife “had begun looking at me the way you look into a sack of fast food when the order’s wrong and you’re already two miles down the road.”

Lucky for everyone involved, Key’s wife Lauren shares his wry sensibility and signed off on the book, but that’s not to say it didn’t take a little coaxing.

Key started writing the book after they separated as a series of letters to her that he never sent.That’s a natural, normal way for me to process things,” he said, “and then I just turned into writing about my marriage. And then I was like, you know, I really think this is a book. I told my agent, and she was like, ‘Dear God, what?’”

When Key told his wife about the book after they reconciled, she balked at the idea. But a year later she was more receptive. When he gave her the manuscript to read, he told her he’d destroy it if she didn’t like it.

“I think she was surprised at how angry and spiteful it wasn’t,” said Key.

From there the couple collaborated on the book, with Lauren providing edits and suggestions, as well as writing her own chapter from her perspective.

As a big fan of memoirs and someone who’s published a few personal essays, I have a pretty good idea of how anxiety-inducing it can be to publish intimate details about your life for all to see. “How to Stay Married” takes it to a whole new level, yet Key appears to be taking it in stride.

“Everybody in our community, everybody who mattered to us knew everything that happened … and so we didn’t have anything to lose,” said Key.

Promoting the book, which publishes June 13, has been more challenging.

“(The affair was) a really terrible thing that obviously has been redeemed and edified and turned into this work of art,” he said, “but it’s really hard to brag on it, which is what you have to do when you’re promoting a book.”

Regardless, Key is eager to share their story, and while he naturally hopes it’s well received, he is braced for blowback.

“Everybody’s own issues and trauma come out when they react to this book,” he said. “I do know people are going to say hurtful things. They’re going to say she’s an evil witch, that I’m a completely neutered, emasculated fool. They’re going to say that we’re evil for writing this in a world where my children can read it. But honestly, all those reactions? We’ve already experienced it in our community. In a sense I just can’t imagine going through anything harder than what we’ve already been through.”

As much as the book is about a marriage, it’s also about a journey of faith. In the beginning Key is a begrudging churchgoer out of a sense of obligation as a father, but at some point, his family joins a few other “broken people” to create their own church. He jokingly likens it to “The Muppet Show,” but it proves to be a tremendous source of strength for his family when they need it most.

“All of the poetry and platitudes and the proverbs and the commandments and the wisdom of the Bible and even the whole purpose of a church, all of those things were all really abstract to me until this happened,” he said.

So what is Key’s secret for maintaining his humor when life throws a curveball?

“Humor is about lightness and playfulness, and that lightness starts with not taking yourself too seriously, with realizing that you’re not the first person to have your problems, and that what feels like the end of the world is not,” he said. “That’s what humor does. It lightens that heaviness. And I’ve always looked at the world through that lens.”

He recalls one night during the middle of his ordeal when he was still in sutures from having his gall bladder removed. He and some friends were sitting on the church steps after band rehearsal drinking “brown liquor,” and he told them a funny story about having his torso shaved in preparation for surgery.

“I’m crying and we’re laughing,” he said. “It’s like laughter was the only way to get the tears out in a healthy way, and it was the only way to keep my heart from breaking, too.

“Laughter has saved my life on more than one occasion.”

Suzanne Van Atten is a book critic and contributing editor for The Atlanta Journal-Constitution. She can be contacted at svanatten@ajc.com.