The 'Life is a Rollercoaster' singer, who split from wife Yvonne in April, also admitted that he doesn't like being single.
"I see myself as a failure. It's been devastating for the children," he is quoted by The Sun as saying.
"Nobody wants to go through a relationship and have kids and think it'll ever break up."
Elaborating on his situation with young children Jack, Marie and Ali, the Boyzone star said: "We obviously don't have the closeness we used to have. That's the hardest thing to bear."
Keating, whose marriage took a significant knock in 2010 when it emerged he was having an affair, added: "Yvonne and I drifted apart - it wasn't working anymore, sadly.
"I'm a free spirit for the first time in years, but I didn't want that. I liked being in a relationship."
Keating is releasing a new solo "proper pop"-sounding album in September, his first in six years.
Watch the music video for Ronan Keating's 'Life is a Rollercoaster' below: