Barry was repeatedly linked with a move to Anfield in 2009 but instead decided to join the early stages of Manchester City's meteoric rise.
The 30-year-old said: "It wasn't an easy decision. I was signing for City on promises being made really and, in football, promises get made all the time.
"From the things the clubs were talking about, I felt City were on the up whereas Liverpool were maybe finding it a bit tougher than City."
Barry's side will face Liverpool in the Carling Cup semi-final first leg on Wednesday evening.