Lady Anne Glenconner can vividly recall one of the final moments she spent with her husband of 54 years.

The 90-year-old, a lady-in-waiting to Princess Margaret for three decades, looked after Lord Colin Tennant, the Baron Glenconner, as he battled prostate cancer.

"We had separate bedrooms," she recalled to Fox News Digital. "I was very upset… and I was crying quietly to myself. I didn’t think he could hear that. He did. He came in and he hugged me. It was the first time in years that he touched me. He said, ‘Was it all bad, Anne?’ I said, ‘No, of course it wasn’t all bad. A lot of it was fine.’ But it was very touching. I always remembered that. And it was a wonderful thing to happen."

Anne Glenconner princess margaret's lady in waiting at an event wearing a floral dress

Lady Anne Glenconner was one of Queen Elizabeth II's maids of honor at her coronation in 1953. (Max Mumby/Indigo/Getty Images)

The British aristocrat passed away in 2010 at age 83. Glenconner, who wrote a book in 2020 about her friendship with Queen Elizabeth II’s younger sister, has written a follow-up published on Feb. 21 titled "Whatever Next? Lessons from an Unexpected Life," which details her troubled marriage. Glenconner, who was inspired by Queen Consort Camilla and her work with domestic violence victims, decided to finally come forward with her story. She said her three children supported her decision. Her eldest two sons passed away in the 1990s.

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Queen Elizabeth II waving at her coronation

Queen Elizabeth II was crowned in 1953. (Hulton Archive/Getty Images)

"[In my first book] I made light of a lot of things," Glenconner admitted. "I didn’t say everything I really wanted to say… [But] I was influenced, I supposed, by the Queen Consort, who has done so much for battered wives and women who are abused. And I had a talk with my children… That’s why I did it."

A black and white photo of a young Lady Anne Glenconner

The former Lady Anne Coke is the eldest daughter of the 5th Earl of Leicester. (Apic/Getty Images)

Glenconner is the eldest daughter of the 5th Earl of Leicester and was childhood friends with both the queen and Margaret. She went on to become a maid of honor at the queen’s coronation in 1953. Glenconner married Tennant, the charming and charismatic friend of Margaret’s, in 1956.

Lady Anne Glenconner and Colin Tennant smiling in a black and white photo

Lady Anne Glenconner married Colin Tennant in 1956. (PA Images via Getty Images)

"He was quite different from anybody else I’d ever met," she said. "He was attractive, he was funny. He was full of wonderful ideas and just made me see that my life could be different. It could be a great adventure. And I completely fell for him. He was also a great friend of Princess Margaret. He was one of the young men she went out with. And I was always rather amazed that he chose me, that he actually wanted to marry me. And a lot of the time we were very happy."

But according to Glenconner, it didn’t take long for her to see her spouse’s dark side.

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"I had seen him lose his temper before we got married," she said. "He always said, ‘The minute we’re married, I won’t need to lose my temper.’ Which, of course, I believed. But he lost his temper on our honeymoon. His promise of not to lose his temper didn’t last long."

Lady Anne Glenconner smiling alongside Colin Tennant during the announcement of their engagement

Colin Tennant, friend of Princess Margaret, and Lady Anne Coke as they announce their engagement on Dec. 16, 1955. (Norman Potter/Central Press/Getty Images)

Glenconner alleged that Tennent was physically abusive behind closed doors. She described him as having violent outbursts. He would allegedly scream at her and throw things in her direction. She claimed in the book that at one point, he beat her with a stick, leaving her deaf in one ear. The attack in question, she claimed, was never repeated. She also suspected that he once spiked her drink so she could loosen up in the bedroom.

Lady Anne Glenconner holding her baby next to Colin Tennant

Colin Tennant and Lady Anne Glenconner outside the London nursing home with their first baby Charles. (PA Images via Getty Images)

"The trouble was one never knew when he would lose his temper," she explained. "And that made it very exhausting to be with him."

Glenconner said she felt as if she was "treading on eggshells" throughout her marriage. The family nanny, Barbara Barnes, who later became a nanny to Princes William and Harry, kept the young children in the dark about the tumultuous union.

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Barbara Barnes smiling in a black and white photo

Barbara Barnes was later chosen by then-Prince Charles and Princess Diana to be the royal nanny for Prince William and Prince Harry. (PA Images via Getty Images)

"I was brought up quite old-fashioned, I suppose," she reflected. "We were brought up [with the idea] that you stick with things. When I went back to my mother once and said, ‘Look, I don’t think I can cope,’ she said, ‘You’re married Anne, you’ll go straight back.’ And I did. And you know, people didn’t divorce so much when I was young. We stuck with it. We tried to make the best of it."

According to Glenconner, Tennant had many mistresses. To cope, she turned to a close friend, who was also married. It resulted in a 34-year affair. Glenconner has never named her lover.

"I lost my trust in men," she said. "We saw each other once a week. We had lunch and the occasional weekend. But he gave me back [my trust]. And I realized that men can be wonderful, that men could be kind, and all that. He made so much difference in my life."

Lady Anne Glenconner wearing a funny hat at a party

Lady Anne Glenconner had a decades-long affair to cope with her tumultuous marriage. She said similar arrangements were quite common among the elite. (Evening Standard/Getty Images)

Glenconner said her lover’s wife was aware of the arrangement. Affairs among the upper crust were very common, she pointed out. And when the mystery man was on his deathbed, his wife invited Glenconner to come to say goodbye.

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"I didn’t know she was going to ask me, but I [was] so pleased when she did," said Glenconner. "She sent me a memento after he died… I think she probably had someone of her own. That’s what people used to do in marriages. That’s how they kept marriages together, really. People had affairs. And yet, we carried on. It was an alternative to divorce."

Glenconner also found solace in her friendship with Margaret, who was struggling in her own marriage. She and the Earl of Snowden had their own extramarital affairs before they eventually divorced in 1978.

Princess Margaret walking with Colin Tennant and Lady Anne Glenconner

Princess Margaret, center, with Lord Colin Tennant and Lady Anne Glenconner in the West Indies. The royal yacht Britannia is in the background. (Ron Bell - PA Images/PA Images via Getty Images)

"[Princess Margaret] knew Colin had a terrible temper," she said. "He used to lose his temper in front of her. So she knew it. Once, he was particularly awful to me and I started to cry. She said to me, ‘Anne, there’s absolutely no point in crying. Come on. Brace up, man up.’ She was very practical. She said, ‘You mustn’t let him see he has this effect on you. You’ve got to be stronger.' And she was in a very difficult marriage herself… [And] for one wonderful year, I lived with her… We would just talk and talk. And in the end, when I left, she said, ‘I really enjoyed having you, Anne. We got on so well. So much better than our awful husbands.’ We just had to laugh. You have to laugh. Otherwise, life is impossible."

Princess Margaret posing next to Colin Tennant

Princess Margaret (1930 - 2002) with Colin Tennant, 3rd Baron Glenconner, on the Caribbean island of Mustique, which Glenconner owns, February 1989. (Slim Aarons/Hulton Archive/Getty Images)

During the final years of her marriage, Glenconner resided in England while her husband stayed in the West Indies. Tennant spent vast amounts of his fortune on transforming Mustique, a tiny island in the Caribbean, into a party resort for the rich and famous. He paid nearly $54,000 for the island in 1958, the New Yorker reported.

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"I stayed with Colin," she said. "We were married for 54 years, but I wouldn’t recommend it to anybody else. But I think that we were lucky toward the end, especially. We didn’t spend a great deal of time together… We spoke to each other on the telephone frequently, two or three times a week."

Lady Anne Glenconner and Lord Colin Tennant posing next to each other in Mustique

Colin Tennant and his wife Anne, on the island of Mustique, which he owned, circa 1973. (Slim Aarons/Getty Images)

But Glenconner said she received a final blow from her husband when he passed away. According to reports, he cut her from his will and instead, left a sizable amount of his fortune to his devoted valet Kent Adonai. It resulted in a legal battle with Tennant’s grandson.

Colin Tennant smiling wearing a hat in Mustique

Lord Colin Tennant at home in St.Lucia. He died there in 2010 at age 83. (David Howells/Corbis via Getty Images)

"I got over everything else, more or less," she said. "All his private things should have gone to the children and me. And I minded about that. I didn’t know how to take it, really couldn’t believe it… After seven years… we took it to court and [my grandson] got half of it back. So something came back."

Today, life for Glenconner has been "wonderful." Since sharing her story, she's received countless letters from women who’ve also endured struggles in their marriages. She’s also penned two historic novels. Her new book offers a list of addresses for those "who are going through a difficult time," including SafeLives, a charity the queen consort supports.

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Camilla, Queen Consort, looking serious at a royal function

Queen Consort Camilla inspired Lady Anne Glenconner to tell her story. (Finnbarr Webster - WPA Pool / Getty Images)

"I’ve never been so happy," she said. "Walking away from a marriage can be quite difficult for many reasons. And I hope my story helps others realize they’re not alone."

If you or someone you know is suffering from abuse, please contact the National Sexual Assault Hotline at 1-800-656-4673.