John F Kennedy Jr, Carolyn Bessette were in counseling during 'tense' final months before plane crash: book

John F. Kennedy Jr. and his wife, Carolyn Bessette-Kennedy, were facing a rocky patch in their marriage before they met an untimely end.

On July 16, 1999, a single-engine private plane Kennedy Jr. was piloting from New Jersey to Martha’s Vineyard crashed into the Atlantic Ocean. Killed with the 38-year-old were his wife, 33, and her sister, Lauren Bessette, 34.

"Several sources corroborated that they were in marriage counseling," author Elizabeth Beller told Fox News Digital. "I see it as a positive that they were taking meaningful steps to work on their issues. And I do believe things were getting better."

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Twenty-five years after the tragedy, Beller has written a new book, "Once Upon a Time: The Captivating Life of Carolyn Bessette-Kennedy." It explores the Calvin Klein publicist’s marriage to "America’s Prince" and their final years together.

Beller spoke to numerous sources who were close to the pair over the years.

"In 1999, there were ebbs and flows in their marriage," Beller explained. "[Their pal] Carole Radziwill said they looked happy and in love. Many other friends said the same thing. But it was a very tense time for them. John’s best friend and cousin, Anthony Radziwill, was very ill [with cancer]. John and Carolyn were very concerned about him. And there was also all that outside pressure."

"It was impossible for Carolyn, who had always been a hard worker, to continue working with the press hounding her at all times. She was suddenly overwhelmed by the press scrutiny. I think it was debilitating for her and I think it sent her into a depression.

"At this time, she was thinking about what else she could do. She was considering making documentary films to represent the underserved… She also needed to see what John’s next step was going to be if he was going to run for office and follow in his family’s footsteps. There was so much expectation because of his last name."

"John was figuring things out, and she had to figure things out, too," Beller added.

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Beller’s book claimed that when Kennedy Jr. proposed, Bessette-Kennedy was hesitant to say yes. They eventually tied the knot on Sept. 21, 1996.

"She was very well aware that, eventually, John would get into politics," Beller explained. "That would mean a public life. But they also weren’t prepared for the frenzy that came upon them from the paparazzi. No one expected that kind of media frenzy. It made it difficult for them to move around and have a normal life."

The tabloids labeled Bessette-Kennedy a "gold digger" and a "coke head." Paparazzi would yell obscenities whenever she stepped out of the couple’s Tribeca loft in hopes of capturing any reaction to sell papers.

Beller’s book claimed that Bessette-Kennedy was so scared to leave her home that she went on antidepressants.

"Carolyn got frightened and retreated," said Beller. "Unfortunately, that painted a more negative narrative in the press. She was depicted as icy and cold. But for many of her friends, she was anything but. She was a good friend to those who knew her."

"John was determined to protect her - he really tried," said Beller.

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Beller said there are still misconceptions that exist around the couple’s final days.

"There was a story that [Carolyn] held everyone up with a three-hour pedicure, and the [accident] was completely on her because they were late taking off," Beller explained. "That’s not true. It’s flat-out wrong. But that story took a life on its own. It was written by a man who claimed to be a friend of Jackie’s, but he wasn’t. But it’s something now etched in stone. She did not tell anyone to change her nail polish three times."

"It was a sticky hot Friday with New York City bumper-to-bumper traffic," Beller shared. "What should have been a 45-minute trip became more like an hour and 15 minutes. They all arrived at the airport within minutes of one another. And unfortunately… the weather changed very quickly. They found themselves in ‘pea soup’ as it’s described. You can’t see."

Beller’s book also noted that Bessette-Kennedy decided at the last-minute to fly with her husband for the July 17 wedding of his cousin, Rory Kennedy.

"Carolyn did not want to go to another event," said Beller. "She had been working for George magazine, which needed financing. It was struggling. She was traveling to possibly look for other publishers and sell ads for the magazine. She was exhausted. And it’s not that she didn’t love Rory Kennedy. I think she just needed a break."

"John was very upset that she wasn’t going," Beller claimed. "They had a huge fight, and she ended up going… And he was thrilled to have her there by his side… I think the fact that they did go together shows they were still committed."

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Beller said Bessette-Kennedy was eager for a fresh start both personally and professionally. She believed her famous spouse wanted to be by her side.

"She was not intimidated by John’s celebrity, but she did not seek that out," said Beller. "She was, however, intimidated by paparazzi following her everywhere. She did not feel fame added real value to her life. She saw fame as the thief of joy… And I think John appreciated that because he had fame thrust upon him his whole life. He recognized that she was not about that. She was not with him for his money and fame. She was with him because they loved each other."

The world will never know if the couple’s marriage would have lasted. But friends of the couple were adamant that they were determined to overcome their difficulties together. According to reports, Kennedy Jr. was thinking about starting a family and was even looking at homes outside of New York City.

"I have no idea if they would have stayed together or not," said Beller. "I do know that they really loved each other. And the way things were going, they were forcing one another – both of them – to grow up in ways that we all need to… The best relationships push you to grow in ways that you might not have if you were either with someone else or on your own. And it’s about how you handle your life, how you handle your spouse’s life. They had an extra entity to deal with when you’ve got that much press."

"I have no idea if they would still be together," Beller reflected. "But it was obvious that they really loved each other. And I think they were doing that work together to make one another grow."

The Associated Press contributed to this report.