Billy McKnight -- Mindy McCready's ex-boyfriend and the father to her oldest son, Zander -- says he's not surprised that the singer took her own life on Sunday afternoon. Right now he is worried for his son, as well as McCready's son with David Wilson, 10-month-old Zayne.

"I feel for her mother, and her family, and especially my son but I can't say that it shocked me," McKnight said during an interview on 'Today' Monday morning (Feb.18).

McCready had twice before attempted suicide, and was thought to be emotionally unstable after the Wilson's death in January. She and McKnight long battled over custody of Zander, whose legal guardian was McCready's mother, Gayle Inge, until the singer disappeared with him in November 2011.

"I'd like to keep those boys together and try to turn my son's life around," McKnight said in the interview. "He's had a rough first six years and he deserves better than this. My heart's broken for him right now, I'm very worried."

When asked if McCready would still be alive and on the road to recovery if she'd been forced to remain in treatment at a hospital, McKnight remains diplomatic, but suggests that could be true. "Mindy does have a way of talking her way out of situations," he says.

"Perhaps staying there and grieving … could have calmed her down," he adds. "But the demons that she hasn't beaten were there, and until she was going to face them something was going to happen and everyone who knows her personally knew that."

It's not clear at this point where McCready's sons are staying. McKnight had previously filed a motion for custody of Zander while McCready dealt with the tragic death of her fiance.