The Princess of Wales wanted “to be a loving wife” but was not given the chance, according to celebrity trainer Jenni Rivett.
Ms Rivett started training with Diana in 1991, after she had been recommended to her by a mutual friend.
Despite always maintaining a professional relationship with the princess, Ms Rivett had a unique insight into Diana’s life and was able to catch glimpses of the sadness caused by her difficult marriage.
Ms Rivett said: “Given the choice she would have stayed and tried to make a happy marriage. She loved Charles.
“She married for the right reasons. She married for love.
“It wasn’t her that asked for all of this. It was sprung upon her.
“She wasn’t the one that wanted to separate or have a divorce.”
Ms Rivett, who trained Diana three times a week at The Harbour Club in Chelsea, London, said what the princess cared about the most was her family and helping the weak.
She continued: “She wanted to be the Princess of Wales and the Queen of people’s hearts.
“She wanted to be a loving mother, which she was, and a loving wife.”
Diana and Charles officially separated in 1992.
Four years later, in 1996, the pair received a letter from the Queen advising them to split up.
The monarch was pushed to advise the future King to break up with his wife after Princess Diana’s bombshell interview to Panorama in 1995, where she laid bare her relationship with the royals and the prince’s love life, royal experts believe.
Upon their divorce, finalised on August 28 1996, Diana lost her Her Royal Highness title, something that deeply affected her, according to Ms Rivett.
She said: “I think she just felt hurt, as you would.
“It was just one thing after another.
“She had to be such an ambassador for Britain and everyone adored her and loved her and she was still the mother of the future king.
“Why should she lose her title?”
Ms Rivett played an important role in the princess’ life, who started battling against bulimia since the early 1980s, when she discovered Prince Charles’s affair with Camilla Parker Bowles.
Explaining Diana had informed the professional trainer about her ongoing battle with the mental health condition, Ms Rivett revealed how the princess didn’t want the illness to bring her down.
She said: “Actually she had such an incredible sense of humour.
“The way that was brought up was with a joke.
“She was just trying to make light of it.”
Indeed, the People’s Princess learned how to integrate workouts in her healing process.
Ms Rivett said that Diana, shortly after they started working together, became “disciplined” and “incredibly dedicated”, and didn’t stop training even after she won her fight against bulimia.
The trainer said: “She knew after every session she would feel amazing.
“It would help her to continue to better herself and feel more and more empowered and make the eating disorder a thing of the past.
“She liked to have a bit of a laugh when she trained and obviously there were days when she was having a really bad day, and I’d be a little bit lenient on her and not boss her around too much.
“She used to feel so great afterwards and the aesthetics are just a bonus.”