But this was just the beginning of a journey — “Oh my God, I hate the word ‘journey,’” Ms. Corman said during rehearsal, opting instead for “thing” — she would embark on, which is not yet over. Somewhere along the way, she began writing it all down, workshopping it with a friend, the director Kristin Hanggi, who reached out in one of Ms. Corman’s low moments and who seemed not to be judging.

Ms. Hanggi encouraged her to turn the writing into a one-woman play, which opens this month at the DR2 Theater. It is directed by Ms. Hanggi (“Rock of Ages”) and produced by the Tony winner Daryl Roth (“Gloria: A Life”), who said she had “admired Maddie as an actress, and am now equally impressed with her writing.”

The title — “Accidentally Brave” — is a reference to the people, the many people, who kept telling Ms. Corman “how ‘brave’ I was,” she said. “I didn’t mean to be brave, but this is what I was dealt.”

Oh, and here’s what she calls the spoiler: Nearly four years later, after rehab, an ongoing 12-step program, couples therapy and much anguished wrestling with questions of ethics, family and the nature of forgiveness, she and her husband remain married.

At home on a recent morning in Harlem, where she now lives with her husband and their 15-year-old twin boys (her daughter is away at college), she sat cross-legged on her bed, her husband beside her, ticking off her list of fears about making their story even more public than it already is.

“I mean, a new fear pops up every day,” she said.

She is afraid she will hurt her children more than they’ve already been hurt. She is afraid of what people will say — not just about what her husband did but of her decision to stay with him. She is worried that, by virtue of staying, she is somehow undermining the women who have so bravely spoken up to say #MeToo — of which she is also one. (Last year, Ms. Corman was one of nine women who spoke out against the playwright Israel Horovitz.)

“And then there are the technical fears: How is it all going to come together,” she said. “So it’s the fears of a writer, the fears of an actor and the fears of a human all combined into one soup.”