Kristen Stewart certainly isn't the first woman in Hollywood to cheat on her man.
While men like Tiger Woods, Jesse James, Arnold Schwarzenegger, Brad Pitt, Ryan Phillippe and others come to mind when it comes to legendary cheating scandals, the gender roles have frequently flipped, with well-known actresses and singers slipping up in their marriage or long-term relationship -- usually with disastrous results. As Twilight fans continue to reel from Stewart's fling with her married Snow White and the Huntsman director Rupert Sanders -- leaving longtime love Robert Pattinson "beyond devastated," according to a source -- Us takes a look at other famous women who've committed infidelity.
LeAnn Rimes: Us Weekly was first to break the story in 2009 that the country singer, 29, cheated on husband of six years Dean Sheremet with Eddie Cibrian, her married costar in a Lifetime flick. "My relationship with Dean was great, but ultimately it wasn't a fulfilling marriage for either of us," Rimes later said. Rimes divorced Sheremet and wed Cibrian in spring 2011.
Meg Ryan: The You've Got Mail actress, now 50, was wed to Dennis Quaid for 10 years when she began a relationship with Russell Crowe, her costar in 2000's Proof of Life. The romance fizzled months later, and she and Quaid divorced in 2001.
Madonna: The Material Girl, 53, strayed from her seven-year marriage to director Guy Ritchie back in 2008 when she secretly hooked up with Yankees slugger Alex Rodriguez, also married at the time. She and Ritchie divorced, and Madonna may have referenced the indiscretion in her 2012 song "I F****ed Up."
Anne Heche: Once Ellen DeGeneres' girlfriend, the actress, 43, was married to Coley Laffoon when she got together with Men in Trees costar James Tupper in 2006. Now divorced from Laffoon, she and Tupper are still together, and are parents to a son, Atlas, 3.
Princess Diana: During her unhappy marriage to Prince Charles (who also cheated with now-wife Camilla), the late mother to Princes William and Harry had a five-year fling with James Hewitt in the late 80s.
Tori Spelling: The actress and reality star, 39, fell for now-husband Dean McDermott in August 2005, while she was still married to Charlie Shanian. "When I met Dean, it wasn't a question--I had to follow my heart. I had never believed in love at first sight, but when I saw Dean, I knew it did exist," Spelling told Redbook of McDermott, with whom she is now expecting her fourth child.
Elizabeth Taylor: Famously married seven times (twice to Richard Burton!) the late, beloved screen legend fessed up to cheating on husband Michael Wilding with Michael Todd in 1956, and cheating on Eddie Fisher with Burton in 1961. "I think I ended up being the scarlet woman partly because of my rather puritanical upbringing and beliefs," Taylor once said. "I couldn't just have a romance; it had to be marriage."