“After nearly five years of marriage, Billy and Katie have decided to separate,” reps for the pair said in a joint statement.
“This decision is the result of much thought and consideration. Billy and Katie remain caring friends, with admiration and respect for each other.”
Rumors have swirled for months that the marriage was on the rocks.
Various reports have linked Lee, a 27-year-old chef and author, with Yigal Azrouel, a dashing 36-year-old Israeli-born fashion designer.
Sources reported seeing them dancing in Miami in January and have claimed that at times Azrouel referred to Lee as “my girlfriend.”
Reps insist that Azrouel was just a friend and that Billy, 60, was happy to skip the parties, fashion shows and fundraisers his younger wife enjoyed.
“Their decision to separate was absolutely unrelated to Yigal,” Joel’s spokeswoman, Claire Mercuri said.
“It was really the age difference that caught up with them,” said a friend of the couple. “They grew apart. She is very career-oriented.”
“She loves going out. She loves the city. When Billy isn’t touring, he’d rather be on Long Island with his motorcycles and boats.”
Still, the friend added, “I can’t imagine the stories about Yigal helped.”
He and Lee married in October of 2004. His nine-year marriage to model Christie Brinkley, the mother of their daughter Alexa, ended in 1994.