New York, June 19 : It looks like the major reason behind singer Billy Joel's separation with his third wife Katie Lee was their age difference.

Sources say that Joel, 60, was just too much of a codger for his 27-year-old wife.

"It really was just an age thing," the New York Post quoted a source as saying.

"She loves the city, she loves to go out and have fun and he prefers to stay at home," the source added.

When Joel isn''t on the road touring, he likes to tinker with his antique motorcycle collection at home on Long Island and sail on his yachts.

"The age difference didn''t seem to be a big deal seven years ago [when they met], but it has become one as they got older. They just grew apart," the source said.

Joel and Lee parted ways after five years of marriage. (ANI)