The star said the band should have walked away following the death of Stephen Gately in 2009.
The Boyzone star was speaking to Newstalk’s Hard Shoulder yesterday about his high-flying boy band days – and what he’s been doing since.
Keating said he missed gigs “terribly” during Covid-19.
"I didn’t realise how much I missed it until was back on stage doing it again; mentally it scarred me,” he said.
"I joined Boyzone at 16 to be a singer - I wasn't to be a songwriter or an artist or any of these things that were created along the way.
"I did that since I was 16 years of age every other day... and then it was gone, it was out of my life for two years.
"It scarred me, it had a mental effect on me, and coming back has been very important," he added.
The former boybander admitted he feels most himself when he’s back touring, sharing that he still has a good relationship with his former bandmates.
"We went out on a high in 2019 with a fabulous world tour... we played countries we'd never been to the first time around.
"We were all across China, Japan, Australia, Asia - all over the place - but it's done now,” he said, ruling out another reunion.
"I think if we ever were to flog it again, and try and come back and do it, it would tarnish whatever was left in my mind anyway."
Keating said the band was as good as done following the shock death of bandmate Stephen Gately in 2009.
“We had 25 great years, for me it finished when Stephen died," he told Newstalk.
"That probably was the end of the band as we knew it, and we probably should have walked away.
"We thought the right thing was to keep it going in Steo's memory, but it never felt right after that ever again.
"The magic was gone, the spark was gone - and I fought for it, I tried to get it back [and] I couldn't get it,” he said.
"For me Boyzone ended then."