The four-piece Blue - including Duncan James, Lee Ryan, Simon Webbe and Antony Costa - shot to fame in 2001 with their debut "All Rise" and sold millions of records worldwide.
They parted ways in 2005 - and James is sure their break-up was down to being overworked.
He tells U.K. TV host Alan Titchmarsh, "I think at the time... we started in 2000 and it literally catapulted us, not just in the U.K., we were all over the world, a big international act selling like 14 million albums - but in order to sell those you've got to really promote hard; you're on a flight every day, in a different country every day..."
"We just had complete burnout as a group and I think if we were managed properly we would probably still be together but that's when the cracks started to happen and we all ended up going our separate ways."
The pop stars made a comeback in 2009 and are representing Britain at the upcoming Eurovision Song Contest later this month - and Costa is pleased the competition coincides with their 10th year in the spotlight.
He adds, "We've learned the hard way but it has done us good for us to come back for our 10th year anniversary."