15 Celebs who slept with their best friend’s partner – #2 will shock you! (With Pictures)

8. Katy Perry and Taylor Swift and John Mayer

Taylor Swift and Katy Perry were great friends once upon a time, leaving adorable Tweets to each other. Taylor Swift was dating John Mayer in 2009, and she lost her bae and her best buddy when their relationship came to an abrupt halt. Katy Perry had snatched him away. Although it is unclear if Mayer and Perry cheated together or he just broke up with T-Swift for Perry, the results are clear. After all this time, the girls are still no longer friends. At least T-Swift got a great song out of the whole affair; Perry and Swift’s fallout is said to be the basis for the song “Bad Blood.” Scandalous!