The divorce between Princess Diana and Prince Charles was a huge Royal Family scandal under Queen Elizabeth's ruling. The Prince and Princess of Wales split-up in 1992 when the divorce was filed. However, their divorce wasn't final until 1996.
About ten-years, after they split-up, Charles married his long-time lover, Camilla Parker Bowles whom he was actually having an affair with during his marriage to Diana. This was what was believed to have caused them to file for divorce in the first place.
Charles suffered from some major backlash after the split. Because of the divorce and the affair Charles had with Camilla, the public felt sorry for Diana and gave her a lot of support. Queen Elizabeth II was very confused about this support for Diana.