Diana finally confronted her
According to the official timeline, Charles and Camilla resumed their affair in 1986, but it wasn't until three years later, in 1989, that Diana finally worked up the nerve to confront her about it. "I was terrified of her," she said later on. But, "The voice inside me had said, 'just go for it.'"
As the story goes, Diana showed up unannounced at a party for Camilla's sister and interrupted a conversation between her husband, his mistress, and another man. According to her biographer, Diana said, “‘OK, boys, I’m just going to have a quick word with Camilla and I’ll be up in a minute.’ The two men then shot upstairs like chickens with no heads" before the princess confronted Camilla saying, "I know what’s going on between you and Charles and I just want you to know that."
Camilla's cutting response? "You’ve got everything you ever wanted. All the men in the world fall in love with you, and you’ve got two beautiful children, what more do you want?"
Diana, in turn, responded, "I want my husband." Mic. Drop.