"I'm not angry," Simpson, 29, said on "The Oprah Winfrey Show" today. "I'm not angry. I'm -- well, I'm a little bit angry ... I'm a little bit angry."
When Winfrey asked why the pop singer's upset, Simpson replied, "Um ... well, I don't want people to know how I am in bed."
Mayer gave Simpson more press than she's seen in months when he said, in an interview featured in the March issue of Playboy magazine, that the sex he had with Simpson was like "napalm" and compared her to "crack cocaine."
Simpson joked on "Oprah," "I could have been worse." Then, laughing, she said, "My phone is ringing off the hook."
More seriously, Simpson said she felt "betrayed" and "disappointed" by Mayer. Even though he sent her a written apology, she said she does not accept it.
"I don't resent him," she said. "I'm just going to let that go."
Simpson has also moved on from the public fascination and media obsession with her weight. She said her lowest point came during the "mom jeans situation," when an unflattering photo of her wearing high-waisted jeans generated headlines about her weight for a year.
"I can't say that I allowed myself to ignore it, because it was everywhere," she said. "The voices were sometimes in my head when I would fall asleep -- the voices of people's judgements."
"Of course it would bother any woman," she continued. "The fact that I was famous last year for gaining 10 pounds was ridiculous."
Simpson told Winfrey that the infamous jeans were a size 4, her current size, and that she fluctuates between a size 4 and a size 6. She said she has no plans to return to her super-slim profile from "The Dukes of Hazzard," in which she played Daisy Duke.
"I love my curves," she said. "I don't ever want to wear a size 0 and weigh 90 pounds."
Still, she said she is amazed that people believe she weighs much more than she does. Recently, during an airport pat-down, an officer told her, "You're really not that big."
After interviewing women around the world for her new VH1 reality show "The Price of Beauty," Simpson told Winfrey that she's decided no one but she can define what beauty is for her.
"I really just finally relaxed," she said, "and I really don't care what people say about my weight, because I think I look great."
Prior to her "Oprah" sit-down, Simpson seemed blase about the Mayer ordeal. In an interview with Allure magazine (which was conducted prior to the release of Mayer's Playboy tell-all) she downplayed his role in her life and said he wasn't responsible for her change in hair color during their 2006-7 relationship.
"He didn't make me go brunette," she said. "John doesn't get credit for making me brunette. He'd like to think so, but he doesn't deserve the credit."
Love has been a battlefield for Simpson. After splitting from Mayer, she dated Dallas Cowboys quarterback Tony Romo, who, according to People magazine, broke up with her the day before her 29th birthday.