She may have been abusive
In Prince Charles: The Passions and Paradoxes of an Improbable Life (via the Daily Mail), sources claim Diana physically assaulted Charles while he knelt to say his daily prayers, beating him over the head. She also allegedly banished his friends from their inner circle, made fun of his required royal garb, and even made him get rid of his beloved dog, Harvey.
The queen demanded it
Long live the queen: In December 1995, Queen Elizabeth demanded, in separate letters to Charles and Diana, that the pair divorce, the Los Angeles Times reported.
“After considering the present situation, the queen wrote to both the prince and princess earlier this week and gave them her view, supported by the Duke of Edinburgh [the queen’s husband, Prince Philip], that an early divorce is desirable,” a palace statement said. “[Queen Elizabeth and Prince Philip] will continue to do all they can to help and support the Prince and Princess of Wales, and most particularly their children, in this difficult period.”
Diana was more down to Earth than Charles
Diana’s brother, Charles Spencer, suggested that Diana was much more connected to normal people than the rest of the royal family, as evidenced by her headline-making handshake with an AIDS patient in 1987. (At the time, the general public was still wary about physical contact with AIDS patients.)
“She was not really a gloves person,” Spencer told People. “She was very real and very about human contact, and what really mattered that day was to get across a very clear message that, ‘I’m going to touch this gentleman—and you can all exist in a community with people who are suffering, and we must help.’… She could make any person, whether they were the grandest or the most humble, totally at ease. It’s an incredible gift.”
A hospital manager who’d worked with the late princess concurred, telling the magazine, “She’d ring up and say, ‘I’ll be along this evening, no cameras, it’s a private visit.’ She’d just come in jeans, jacket, baseball cap or from a dinner or a gala in all her finery and have a cup of tea to see the patients.”