He also went as far as to praise her influence on Lennon's solo career.
"I don't think he would have written 'Imagine' without Yoko, so I don't think you can blame her for anything. When Yoko came along, part of her attraction was her avant garde side, her view of things, so she showed him another way to be, which was very attractive to him.
"So it was time for John to leave, he was definitely going to leave one way or another," he added.
McCartney placed more blame for the group's demise on Allen Klein, the businessman, who succeeded former manager Brian Epstein in 1967.
The music legend said that it was Klein who set him fighting against the others.
"I was fighting against the other three guys who'd been my lifelong soul buddies. I said I wanted to fight Klein," he said.