Why Princess Diana Feared She'd Lose William and Harry to the Royal 'Establishment' Amid Split from Charles

In the years just before and after her separation from Prince Charles, Princess Diana was weighing a tough decision.

The royal — who had been privately struggling with bulimia, depression and her husband’s longtime affair with his eventual wife, Camilla (then Parker-Bowles, now the Duchess of Cornwall) — wanted to open up about the mistreatment she felt she’d been subject to throughout her marriage.

And as it became clear that her marriage was unraveling, she grew concerned about losing everything. Her friend James Colthurst, tells PEOPLE in this week’s cover story that she feared that her children, Prince William and Prince Harry, would be kept away from her post-divorce if she opened up.

“She wanted to tell the world how ghastly things had been and how appalling,” Colthurst says. But she saw that there could be consequences: “She was worried she would be blamed and then sidelined. And then would lose her position as mum.”

Colthurst is among the friends, family and confidants remembering the late princess in PEOPLE’s cover story and on a two-night television event from PEOPLE and ABC, The Story of Diana, airing on ABC on Aug. 9 and 10 at 9 p.m. E.T.

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Of course, Diana did eventually open up. In secret, she spoke to author Andrew Morton, supplying him with the material for a tell-all book, Diana: Her True Story, which was published in 1992, the year she and Charles separated. Then in a famous 1995 interview with the BBC’s Panorama, she spoke out further, stating that there were three people in her marriage to Charles.

Despite her fears, she did not lose her children: Though Prince Harry recently said in a new ITV/HBO documentary that after his parents’s separation, he never saw enough of either of them, he and Prince William continued to split their time between their parents.

For full PEOPLE coverage of the 20th anniversary of Princess Diana’s death:

•Pick up PEOPLE’s cover story on newsstands now

•The Story of Diana, a two-part television event from PEOPLE and ABC, airs on ABC Aug. 9 and 10 at 9 p.m. E.T.

•PEOPLE’s special edition Diana: Her Life and Legacy is available now

•Princess Diana: Behind the Headlines is streaming on the new People/Entertainment Weekly Network (PEN). Go to PEOPLE.com/PEN, or download the PEN app on your favorite mobile or connected TV device