How a Polyamorous Mom Had ‘a Big Sexual Adventure’ and Found Herself

For anyone prone to experiencing secondhand embarrassment, there’s a scene in Molly Roden Winter’s debut, “More: A Memoir of Open Marriage,” that should come with a warning.

Winter is at her home in Brooklyn. She has just had sex with her boyfriend while her two children sleep upstairs. Her husband, Stewart, consented to her tryst, but feeling guilty, she dashes naked into the kitchen to text him: Don’t worry, she writes, “he has nothing on you as a lover.” But instead of texting her husband, she accidentally sends the message to her boyfriend, who leaves in a huff, and later breaks up with her. Winter, devastated, begs her husband to come home to comfort her.

“I still get a little nauseous thinking about it,” said Winter, 51, who was sipping tea in the living room of her bright and airy townhouse in Park Slope, Brooklyn. “Talk about the cringiest, cringiest, most awful thing that could happen.”

It’s far from the only agonizing and breathtakingly candid scene in “More,” which documents Winter’s often turbulent experience of open marriage — the resentment and jealousy she felt toward her husband’s girlfriends, the flashes of guilt and shame, and the challenges of juggling her obligations as a wife and mother with her pursuit of sexual and romantic fulfillment.