Cooper, once linked to 1970s sex symbol Raquel Welch, has long refuted rumors that he ever cheated on his wife of 37 years, Sheryl Goddard.
Dick Wagner, Cooper's longtime guitarist, backs his friend's claims in a new autobiography called "Not Only Women Bleed," saying that the "Hey Stoopid" musician "has a propensity towards being faithful to his girlfriend."
According to the account, Wagner and Cooper were invited up to Welch's suite at the Fontainebleau hotel in Miami in 1976.
“I sensed something was going on . . . at least in Raquel’s mind.” Wagner said.
“You gotta do it at least one time for all us horny bastards in the world," he recalls telling his friend, who managed to stay true to his then-girlfriend and future wife, even after Welch showed up at golf the next day asking Cooper, "Can I be your caddy?"
Cooper married Goddard in 1976. They now have three children.