Hugh Hefner was 86 when he married 26-year-old Crystal Hefner, and the widow is now baring all.

The Playboy founder’s third and final wife has written a memoir, "Only Say Good Things: Surviving Playboy and Finding Myself." 

The title comes from Hefner’s own words to his young bride – only say good things about him.

"I think after leaving the [Playboy] mansion and being away for five years, I was in a lot of therapy," Crystal, now 37, told Fox News Digital. "I realized that the mansion affected me more than I thought. I just wanted to tell the truth about my time there and hopefully help others."

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Crystal’s marriage to Hefner ended when he died in 2017 at age 91. She claimed their nearly five-year union was "emotionally abusive," noting in her book that Hefner "could be charming" but also "cruel."

"Over a little bit of time, I gained a bit of weight, and he told me that I needed to tone up," Crystal claimed. "Then he started telling me what color nails I could have and couldn’t have. [I had to] wear more colorful shirts, wear ‘the flag,’ which means the Playboy logo on my body, somewhere on my shirt. I had to dye my roots, bleach my roots. If that was growing out, he would tap it and tell me to go fix it."

Crystal also alleged that during their marriage, she had a restrictive curfew and was required to rush back to the Playboy Mansion before dark. The book claimed that if she was late, Hefner would scream at her.

"A lot of the other girls talked about a nine o’clock curfew or 9:30," she explained. "When I was there, it was a 6 p.m. curfew. A lot of times I was home before it was even dark outside. He disguised this curfew as a schedule, so it would be 6 p.m. movie night [on] Thursday, Friday, Saturday, Sunday. And then I’d have little breaks on Monday and Wednesday when he was occupied with the guys for ‘Manly Night’ and cards. … It was this super strict schedule. … I had to be in before dark."

The one-time San Diego State psychology major said Hefner’s harsh remarks about her weight, along with his no-nonsense rules and expectations to "perform" in the bedroom whenever the mood struck, took a toll on her. But in looking back at their marriage, she admitted that her late husband, a leader in America’s sexual revolution, was a complicated figure.

"I remember when [former girlfriend] Holly [Madison’s] book first came out," she said. "I was still living at the mansion. I was very defensive of Hef. I’m like, ‘Oh, I can’t believe she could do that.’ But after I left to heal, I’m like, ‘OK, everything she’s saying is true.’ And then I saw the A&E documentary, ‘Secrets of Playboy,’ and I thought, ‘Yeah, a lot of what these women are saying is true.’

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"Some of the things were far-fetched, trying to tie Hef to something like in Geneva that was with somebody else, but a lot of it’s true," Crystal continued. "Hef was a very complex person. He wasn’t all good, and he wasn’t all evil. He wasn’t a predator. But, at the same time, he was also narcissistic and was a misogynist, and we have to be honest about that moving forward.

"I’m still on the board of his foundation," she noted. "The other two members of the foundation, they’re fully aware that he can be all types of things."

Crystal described growing up in a "broken home" and losing her father when she was just 12 years old. After she came across her stepfather’s copies of Playboy, she dreamed of being beautiful like many of the blonde bombshells that left her in awe.

"I thought, ‘They’re so powerful — they have the world at their feet. I want to be just like them,’" she recalled. "I didn’t have any means, and I thought I just made myself small all the time. I’m like, ‘It would be nice to feel powerful or beautiful.’ I was very drawn to that."

In 2008, Crystal attended a Halloween party at the Playboy Mansion. Dressed as a French maid, she immediately caught Hefner’s eye.

"Why he chose me? In the very beginning, I think it was purely based on [the] physical," she explained. "I think, by that point, I had made myself into the Playboy ideal, which is the Hugh Hefner ideal. I think that becoming his wife … maybe I brought some kind of calmness to his life, or maybe he wanted a good PR story for the end of his life. I’m not sure, but I do think about that often still."

While Crystal was never in love with Hefner, she felt compelled to protect the elderly man whom she alleged was clinging to his image of the past. While life at the mansion seemed decadent for someone who struggled growing up, Crystal said she saw a different side to the hedonistic hot spot once she moved in.

Crystal claimed that the mansion was "run down" and moldy as the birds located on the property were dying of thirst. While Crystal felt "trapped," she still felt an urgency to protect Hefner in his later years.

"When I was told what to wear, what to do and to lose weight, I thought, ‘I’m going to be better. I can do better,’" she said. "I don’t know why my mind went there at that time instead of ‘How dare you treat me this way?’ But I’m not sure what compelled me to protect him. 

"Maybe, in a way, I felt sorry for him. Maybe, in a way, it was Stockholm Syndrome, which I truly believe happened there because it was such a bubble. But I did feel compelled to protect him for some reason."

While living at the mansion, Hefner gave his girlfriend a ring.

"He didn’t ask me to marry him," she said. "He just handed me a ring in a box and said, ‘I hope it fits.’ And, at that time, I just thought, ‘Maybe he wants this good PR story, ending his life with a wedding.’ We hadn’t talked about it before, so I just made assumptions. If I were to say no, then I would’ve had to leave right then, and I wasn’t ready to leave."

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After Crystal accepted Hefner’s proposal, she broke off the engagement days before she was supposed to walk down the aisle. After a tumultuous relationship with Dr. Phil’s son Jordan, she returned to marry Hefner. The magazine quickly capitalized on her "Runaway Bride" image, Crystal alleged.

Looking back, Crystal said, she saw herself as more of a caregiver than a wife.

"Toward the last few years, I felt like I had to be there for him," she said. "It was getting harder for him to do things and walk, and he wanted to be remembered as the man, the man everyone saw him as or thought he was, which really isn’t true. But I tried hard to help him protect his image until the very end."

Playboy didn’t immediately respond to Fox News Digital’s request for comment about Crystal's book. At the time of A&E’s 2022 docuseries, a spokesperson issued a statement.

"Today’s Playboy is not Hugh Hefner’s Playboy," the statement said. "We trust and validate these women and their stories, and we strongly support those individuals who have come forward to share their experiences. As a brand with sex positivity at its core, we believe safety, security and accountability are paramount.

"The most important thing we can do right now is actively listen and learn from their experiences," it added. "We will never be afraid to confront the parts of our legacy as a company that do not reflect our values today.

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"As an organization with a more than 80% female workforce, we are committed to our ongoing evolution as a company and to driving positive change for our communities."

Today, Crystal lives in Hawaii, where she runs a lychee farm. She has "nothing to hide anymore."

"I hope he would be OK with this book that I’ve written," she said about Hefner. "I hope that he would give his blessing. His foundation sticks up for First Amendment rights, freedom of speech and expression. So, I hope that he is fine with me telling my truth."