"I knew it was coming to an end a little bit from the previous 12 months. I was aware of what was going on behind the scenes," he told Stretty News TV. "There were some public things that had happened that were pushing it a little bit.
"I was disappointed when he left but I was also disappointed when Nicky Butt left. I was disappointed when my brother left, I was disappointed when Roy Keane left and I was disappointed when Denis Irwin left. They were a massive part of our lives and our careers at United.
"It wasn't just the lads around me - David, Phil [Neville] and Nicky and such like. When a player of real magnitude left there was a void. They're a big miss. You obviously move on, you just move on. Just as when I left or when other players left, the club is big."
He added: "When David left, to be honest with you, at the time 'sad' probably wasn't the right word. I was probably relieved a little bit. For him, for the club - it could never end badly, that relationship.
"David had done so much for the club and the club had done so much for David. He loves the club and the club loves David. It could never end badly. His time had probably come at United where it was right to leave.
"There was a bit of me that was relieved that that tension, that little bit of an underlying thing that was there had gone. He was a brilliant player and I loved playing with him and knew exactly what he was going to do and he knew exactly what I was going to do."