She stayed, and it cost her more than she ever imagined.

For nearly two years after Bernard Madoff confessed to running the largest Ponzi scheme in history, Ruth Madoff — who fell in love with him at 13 and married him at 18 — stood by her husband, a man the rest of world saw as a cold-blooded monster.

She stayed despite doubts about his fidelity, hostility from friends who became his victims, and a deepening rift with her two sons, who insisted she cut herself off from him.

She finally cut the knot last fall, Madoff said. “You’re going to have to leave me alone and not call,” she bluntly told her husband. When he persisted, she changed her number.

After years of silence, Ruth Madoff agreed to talk with a New York Times reporter because her surviving son, Andrew, asked her to help promote “Truth and Consequences: Life Inside the Madoff Family,” abiography by Laurie Sandell to be released today by Little Brown.

Tiny and slightly stooped, Ruth Madoff arrived at the interview, held at her sister’s home in Boca Raton, Fla., dressed in cropped white canvas pants and a gray knit top. She spoke in a soft throaty voice, frequently on the edge of tears, about the devastation of her family — and thousands more around the world.

“It’s so sad,” she said. “Everything that I think about the victims — it’s hard to face, because there’s nothing I can do about any of it.”

Like so many of those victims, she now has just a thin slice of the life she once had. Turned down by several Manhattan landlords, she lives in a borrowed townhouse in a gated community in southeast Florida. She is facing litigation and is “afraid to spend a penny.” The damage her husband inflicted on his victims still shocks her, she said — “it was beyond anything imaginable.”

But she has slowly rebuilt a life. She worked with children who needed extra emotional support, and now spends up to four days a week as a volunteer for Meals on Wheels, where she has a small network of new friends.

A few things have not changed. Some Madoff victims still accuse her of complicity in the crime — which she denies — and attack her on the Internet or in the media whenever she is mentioned in the news. It has been that way since the day her husband, a respected Wall Street statesman, was arrested for stealing at least $17 billion in cash and $64.8 billion in paper wealth from victims around the world, including many in his extended family.

Madoff struggled to explain why she had stood by her husband, a decision that seemed to catalyze the public hostility toward her that persists to this day. Indeed, she and her husband felt so hopeless and embattled in the weeks after his arrest that they tried to commit suicide by swallowing large handfuls of Ambien, she said.

In an email from prison, Bernard Madoff confirmed that he and his wife “made a feeble attempt” at suicide “while in a severe state of depression. Fortunately, we woke the next morning very sick but alive.” He concluded, “Please understand this is very difficult to admit.”

She stayed with her husband, she said, because “I come from a generation where marriage meant staying put, for better or for worse. This was agonizing, but I couldn’t abandon the man with whom I spent essentially my entire life.”

So she visited him a handful of times at a federal prison in Butner, N.C. When she finally cut her ties to her husband, it was too late for her son Mark. After his suicide attempt in October 2009, Mark Madoff had begged her to walk away from his father. But she didn’t act quickly enough, she said. On Dec. 10, 2010, the second anniversary of his father’s arrest, Mark Madoff hanged himself.

One more time, Ruth Madoff called the prison — to tell her husband that their firstborn was dead. She spoke first to a chaplain, she recalled, near tears. “He got Bernie — he told him before I spoke to him. I could barely get it out.”

Madoff said she was “haunted” by her failure to act soon on her older son’s appeals. “I had no idea it affected Mark so brutally,” she said, tears spilling over.

That memory determined her response when, early this year, her surviving son, Andrew, asked her to help promote the new book. Despite her lawyer’s opposition and her own fears, she barely hesitated.

“I wanted to do what he wanted me to do,” she said. “I hadn’t done it in Mark’s case, and I will regret that until my dying day.”

Unlike his mother, Andrew Madoff did walk out when his father confessed. But that did not exempt him from the suspicion his mother still faces.

Like their mother, both Madoff sons were the targets of public accusations that they had been involved in the scheme.

Ruth and Andrew Madoff deny that, and neither they nor Mark were ever the focus of a criminal investigation. “I would have no way of knowing” about the elaborately concealed fraud, nor did her sons know anything, Ruth Madoff said.

Andrew Madoff, casually dressed for his interview in jeans and a dark sweater, was even more emphatic. “From the beginning, when this whole thing started, I’ve wanted to talk and tell my story.” When Hooper, his fiancee, suggested he work with Sandell on an authorized biography, he immediately agreed.

Why? “I’m hoping that when people have heard my story, they will judge me a little bit less harshly,” he said.

He says he thinks his mother should file for divorce, but she sees that as a meaningless gesture. He also says that working on the book has helped his mother deal with her anger over his father’s betrayals and will make a hostile public more sympathetic.

Ruth Madoff doubts that, she said. But she said she would like to emerge with two precious things: She hopes to have sewn together at least some pieces of her tattered family life. And she hopes to feel “that I can walk down the street and hold my head up a little bit.”