According to Encyclopedia Britannica, files on Martin Luther King Jr.’s surveillance by the FBI that were made public in the 1970s because of the Freedom of Information Act showed that he did cheat on his wife. Since then, a number of serious academic studies of his life have shown that he had what Bio.com calls “adulterous relationships.”
In an article called “The FBI and Martin Luther King” published in The Atlantic on July 1, 2002, by Pulitzer Prize-winning King biographer David J. Garrow, it was written that on October 10, 1963, U.S. Attorney General Robert F. Kennedy gave the FBI permission to wiretap King’s phones for the first time. One of King’s top advisors, Stanley David Levison, was thought to be an important member of the American Communist Party. This was the reason why. In 1956, Levison met King and began giving him advice on the side. Even though King’s friends and family told him to stay away from Levison, King kept going to him for advice. Kennedy was suspicious of King because he was friends with Levison, and the FBI found out about his extramarital affairs when they wiretapped him to find out if he was a communist, which they never could prove.
The Encyclopedia Britannica says that there is still disagreement about Martin Luther King’s legacy, but it is generally agreed that, even though he was flawed and made mistakes, he was also a visionary leader who was deeply committed to getting civil rights through peaceful means.