Keith Urban Checks Into Rehab
"I deeply regret the hurt this has caused Nicole and the ones that love and support me," Urban says in the statement. "One can never let one's guard down on recovery and I'm afraid that I have.
"With the strength and unwavering support I am blessed to have from my wife, family and friends, I am determined and resolved to a positive outcome."
The statement adds that all of Urban's immediate appearances promoting his forthcoming CD will be postponed.
He had been due to perform at the Mohegan Sun Casino in Connecticut Friday night, but cancelled the sold-out show. "We obviously feel bad for the situation that Keith's going through," Mohegan Sun CEO Mitchell Etess tells PEOPLE. "He's been here several times, and we're just interested in his recovery."
Urban, who turns 39 on Oct. 26, and Kidman, 39, were married on June 28 in Sydney, Australia, after meeting in January 2005.
He has been in rehab before, and has said his song "You're Not My God," from his 2002 album Golden Road, is about his battle with drug addiction.