Glennon Doyle has written two best sellers, raised over $25 million for people in need through her nonprofit Together Rising, considers Oprah a teacher and friend, and has more than 700,000 Facebook followers. But sometimes even she is a disappointment.

“I’m terrible at friendship maintenance,” she said over breakfast last month at Manhattan’s Whitby Hotel. “If you have a crisis, there’s nothing I wouldn’t do. If your dad died, if you need to write a eulogy, I’ll drop everything. But then I will never call you; I’ll never check in. I’ve spent a lot of time in shame about this, but I feel like I’m doing a good job with the mom thing and the work thing and a freshly good job with the partnering thing.”

Friendship is among the many topics — including sisterhood, body image, cheetahs (just go with it) and her efforts to better understand racism as a white woman — covered by Doyle in her third memoir, “Untamed,” coming out from The Dial Press on Tuesday. You may be wondering: Why a third memoir, particularly when the second, “Love Warrior,” came out in 2016?

Doyle, 43, answers the question in the first sentence of “Untamed”: “Four years ago, married to the father of my three children, I fell in love with a woman.”

She was in Chicago, promoting “Love Warrior,” which explores how she and her then-husband, Craig Melton, had recommitted to their marriage after he confessed to cheating on her multiple times. Her fans, many of them avid readers of her Christian parenting blog, Momastery, were counting the days until the book went on sale. Flatiron, her publisher, had announced a first printing of 150,000 copies, an extensive tour was in the works and “Love Warrior” was about to be named an Oprah’s Book Club pick. Inconveniently, that was when she met Abby Wambach — World Cup champion, Olympic gold medalist, former captain of the U.S. women’s soccer team — who was promoting her own memoir, “Forward.”

“We couldn’t have been a worse fit for each other,” Wambach said in an interview. “Glennon had a husband and three children and lived in Naples, Fla. I’d been sober for a month, my marriage was falling apart, I’d just left my soccer career of 30 years and I lived in Portland, Ore.”

“My whole being says, There She Is,” Doyle writes in “Untamed” about their first interaction. “I ask if I can hug her because what if this is my only chance? She smiles and opens her arms. Then — the smell that will become home to me — skin like powder and fabric softener blended with the wool of her coat and her cologne and something that smelled like air, like outdoors, like crisp sky, like a baby and a woman and a man and the whole world.”

How they navigated from that night to their wedding a year later is the central thread of “Untamed.” Spoiler alert: The story appears to have a happy ending, or beginning. Wambach and Craig Melton have even played together on the same adult-league soccer team.

Of Melton’s support of her relationship with his and Doyle’s children, Wambach says, “It’s a gift I don’t know if I can repay — probably the most selfless act of grace or love I’ve ever experienced.”

In an interview, Melton said: “I’ve seen a lot of people in similar situations where the two exes put their egos first and the kids suffer. I wanted to be the best role model I could, knowing there was some damage that was my fault in the relationship.”

Doyle grew up in Burke, Va., in a family with a strong tradition of putting words on paper. That she became a writer didn’t surprise her younger sister, Amanda Doyle. “Glennon is the one everyone always went to when they needed to write their wedding vows or something important,” she said.

Starting when her children were toddlers, Glennon Doyle sent daily email musings about recovery, faith, parenting and marriage to a handful of close friends. She’d follow up a few hours later to get their thoughts; most of the time, they hadn’t had a chance to read her dispatch. In 2009, after a friend sent Doyle a website-building tutorial, she took the hint, and Momastery was born.

“The only reason my writing ever got out into the world was because my friends didn’t want to read it anymore,” Doyle said. “The very first time I wrote something and people I didn’t know were like, ‘Whoa, that’s honest,’ I felt a prickle at the back of my neck. I felt this ‘we-ness.’”

Whitney Frick, editorial director at The Dial Press, remembers reading the proposal for Doyle’s first memoir, “Carry On, Warrior,” as it came out of the printer, page by page. “I wasn’t religious, wasn’t married, hadn’t had a baby,” said Frick, who worked with Doyle at another publisher at the time, “but I could still relate to what Glennon was saying. I thought, ‘I want that voice in my head!’”

Others do, too. “Lessons From the Mental Hospital,” a TEDx talk by Doyle in 2013, the year that “Carry On, Warrior” came out, has been viewed more than three million times. Frick remembers 400 people showing up that year for one of Doyle’s readings in Connecticut, and another at Books-a-Million near Doyle’s Virginia hometown, where readers arrived hours in advance. “There was no stage or microphone,” Frick said. “She climbed on a ladder, opened her arms and yelled, ‘Hello, everyone!’”

It was around that time that Doyle was learning about her husband’s infidelities. Reflecting on it in her new book, she writes: “The revelation of my husband’s betrayal did not leave me feeling the despair of a wife with a broken heart. I was feeling the rage of a writer with a broken plot.”

Writing “Untamed” came with its own struggles. Elizabeth Gilbert, a friend and the author of “Eat, Pray, Love,” lent an ear and some critical feedback when Doyle shared an early draft.

“I started reading to Liz, and I’m watching her, and she’s literally sinking deeper and deeper into the couch,” Doyle said. “She was like, ‘You’re writing a book about wildness and you’re not writing it wild.’”

Gilbert suggested that Doyle cut out all the “connective tissue” and tell one personal story after another. “That’s where Glennon shines, and that’s what we all want from her — intimate, funny, moving stories that will reflect light back on our own existence,” Gilbert said.

Doyle said she writes from her scars, not her wounds. She has learned to give the events of her life some breathing room before pouring them onto the page or the screen. When she announced her relationship with Wambach on Instagram, the responses were swift, supportive and, considering they came mostly from strangers, surprisingly familiar. One follower wrote: “You are so brave to put your soul on social media. Wishing you all the love we all deserve.” Another sent best wishes and a caveat: “This picture would suggest that you’re using your hair straightener again and that concerns me. You have amazing hair and it should remain in its natural state.”

Doyle’s biggest fans have long known that her journey hasn’t been without its bumps, but she discloses even more of them in “Untamed,” including the turmoil she and her family went through (“Good mothers don’t break their children’s hearts to follow their own”) after she fell in love with Wambach.

Will another seismic event disrupt the release of “Untamed”? “I’m kind of scared because something big usually happens,” Doyle said. “This book is what I’ve been wanting to say since I was born. I’ve finally gotten to the point where what I want for the future is more of what I have. Not something different.”

Follow New York Times Books on Facebook, Twitter and Instagram, sign up for our newsletter or our literary calendar. And listen to us on the Book Review podcast.