The singer explained that a want to tour with his own headline concerts means he would not be able to remain with Take That on a permanent basis.
"The gigs have been absolutely amazing - the best period of my career so far with those boys," The Sun quotes Williams as saying.
"Sharing it with somebody is much better than doing it by yourself, but then ego, want, need and a whole heap of other things kick in."
He added: "And you start preparing for your own tour... and the other boys are going away for a bit and I don't really know what's on the cards with them.
"But we have to ride again, we have to - it's too much fun."
Williams made the claims following Take That's final 'Progress' tour date in Germany on July 29.
The group recently denied that they had fallen out with Williams on tour, while the 37-year-old has confirmed plans to embark on a solo jaunt in the near future.
Take That will officially release their new single 'When We Were Young' on August 22.
Watch the music video for 'When We Were Young' below: