Billy Joel's Wife Jumping Off With Not Gay Designer

Is Billy Joel's 27-year-old wife cheating on his with a "hunky" fashion designer?

Hmmmm... probably.

Billy Joel, who will turn 60 in May, is being advised by friends to dump Katie Lee when his current tour ends in November.

Why?

Katie has been jumping off with Yigal Azrouel, a 36-year-old Israeli-born designer for almost a year now, according to the Enquirer. (The two are pictured together, right.)

"Billy is furious. His wife's relationship with this guy is causing a split in his marriage. Initially, Billy thought it was great that she met a new friend, someone to occupy her time while he trudges through a long tour schedule. But now he's become very concerned. Billy initially thought Yigal - being a male fashion designer - was gay. But when someone told him the guy was heterosexual and had women hanging all over him, Billy began to worry," a source said.

If I were old man Billy Joel, I would have cause to worry, too.

Just saying.