Illustrious Rolling Stones frontman Mick Jagger has earned a reputation as a party animal and a ladykiller—so it's no surprise that he's acquired quite a few notches in his bedpost by now, at age 68. (In fact, one might expect his bedpost to be whittled away to nothing more than a toothpick.) But Mick: The Wild Life and Mad Genius of Jagger, a new biography from Christopher Andersen (who's been covering the Stones since 1969), claims that Jagger’s promiscuity may be deeper and more pathological than typical rock star frivolity. Andersen, who estimates the rocker has had as many as 4,000 partners, tells CBS in an interview: “He does have personal problems. Jerry Hall proclaimed after putting up with his infidelity for 23 years that he was a sex addict and she asked him to get help." In what sounds more like a storyline from a sequel to Fifty Shades of Grey than a real-life experience, Andersen recounts: "Keith [Richards] asked him to get help and they were thrilled when he sought help from a sex therapist, until he seduced the sex therapist.” The biographer, who interviewed the legend's friends, relatives and mistresses—but not the Stone himself—suggests that this behavior stems from a dark place, describing Jagger as "somebody who has personal demons and compulsions.” Maybe having "moves like Jagger" isn’t cause to brag after all—but rather a cry for help.