Bon Jovi guitarist Richie Sambora has entered rehab, a rep for the band tells PEOPLE exclusively.

"Richie Sambora has entered an undisclosed treatment facility in Los Angeles," the rep said in a statement. "He asks that you respect he and his family's privacy at this time."

The specific nature of Sambora's substance-abuse problem was not disclosed.

It has been a difficult year for Sambora, 47. He and actress Denise Richards broke up several months ago after dating for about a year. In April, his divorce from Heather Locklear was finalized. And that same month, his father died of lung cancer. (Richards accompanied Sambora to the funeral as a show of support, though they had ended their relationship by that point.)