Ruth Madoff, whose husband Bernard L. Madoff is serving a 150-year prison sentence for conning investors out of billions of dollars, was more deeply hurt by his alleged long-running extramarital affair than by his fraud, according to a new book.

In a confrontation with her son Andrew Madoff, she said that was “the most hurtful thing” that ever happened to her, the book says.

When she wondered aloud why Bernard Madoff didn’t just leave her, Andrew Madoff reportedly offered one possible explanation: In a divorce, Bernard Madoff’s finances would have been scrutinized.

Left hanging is the implication that if Ruth Madoff had left her husband and forced such an accounting, his house of cards might have collapsed earlier.

The book, “Truth and Consequences: Life Inside The Madoff Family,” is to be released Monday. The Washington Post obtained a copy Friday. The account is written by author and magazine writer Laurie Sandell, who says she was approached by Andrew Madoff and his fiancee, Catherine Hooper, to write about the family’s painful experience. Ruth Madoff also cooperated, Sandell writes.

Sandell previously published “The Impostor’s Daughter,” a memoir about her life as the daughter of a charming father who she says was actually a con artist.

Their father’s crime

The Madoff book, which follows others about the epic scandal, portrays the Madoff sons as unwitting victims of their father’s crime. It describes the lavish lifestyle the family once enjoyed, the gathering signs of trouble and Bernard Madoff’s dramatic confession as the fraud became unsustainable. It also describes the fallout.

In the weeks before Madoff’s fraud was exposed, Andrew Madoff gave his fiancee a three-carat diamond ring and the family flew by private jet to Palm Beach, Fla., where the bill for a poolside cabana was as much as Hooper’s monthly rent, the book says.

But Bernard Madoff was already showing signs of stress, complaining that amid the financial crisis, investors were demanding their money. When a granddaughter asked over dinner whether he was going to have to shut his business, he told her that everything was fine and that she should have more crab.

Back in New York, his sons realized something bad was happening. First Madoff said he could not immediately provide cash for Andrew to wrap up his divorce; then he pressed to pay employees’ bonuses prematurely.

When he confessed to his wife and sons that his business was a lie and a Ponzi scheme, Ruth Madoff asked, “What’s a Ponzi scheme?”

A family wounded

The family was torn apart, the book says. The sons were furious with their mother for staying by their father’s side, and she lashed out at Andrew for spurning his father and refusing to sign a bail bond, the book says.

Besieged and vilified, Bernard and Ruth Madoff attempted unsuccessfully to kill themselves with sleeping pills, the book says. But first, Ruth mailed favored pieces of jewelry to members of her family.

The couple’s embittered son, Mark, made a similar suicide attempt in a New York hotel and later told Andrew, “How else am I supposed to make Mom and Dad understand what they’ve done to me?”

Andrew told Mark that Mark couldn’t abandon his children to send a message to his parents, the book says.

But later, alone in his home while his 2-year-old son slept in the next room, Mark Madoff attempted to hang himself with a vacuum cleaner cord. When the cord snapped, he successfully committed suicide, hanging himself with his dog Grouper’s leash. That was after assuring his former wife that he and his young son “are going to have a fun night together,” the book says.

The collapse of the Ponzi scheme and the loss of money left Ruth Madoff’s sister and brother-in-law, both in their 70s, driving airport taxis for a living, the book says.

Surrounded by victims

The book says that Ruth Madoff, living in Florida, is surrounded by her husband’s victims.

“Even my gynecologist here in South Florida told me that his mother was a victim,” she is quoted as saying. “I froze and said, ‘I’m so sorry.’ ”

The book says Madoff confronted her husband about his affairs during a prison visit, saying she regretted never having resolved her past accusations. He responded with a denial, the book says.

But the book describes Madoff as so devoted to her longtime husband that she could not accept Andrew’s assertion that his father was a horrible person who deserves to be rotting in prison.

“I can never forgive him,” she is said to have told Andrew, “and yet I’m not angry with him.”