After spending decades as part of Crosby, Stills & Nash — and many of its various permutations — Graham Nash says he's walking away from the group.

Following up on a recent interview in which he blamed his CSN departure on poor treatment from his longtime creative partner David Crosby, Nash further detailed his dissatisfaction in conversation with Billboard, making it clear that as far as he's concerned, the trio has harmonized on its last song.

"Right now, I don't want anything to do with Crosby at all. It's just that simple," said Nash. "In my world there will never, ever be a Crosby, Stills, Nash & Young record and there will never be another Crosby, Stills & Nash record or show." He declined to say specifically what Crosby had done, simply saying that, "I was letting Crosby be who he is. I let people play their hand in front of me, and I let him do it and then I make a decision."

Facing the release of This Path Tonight, his first solo album in nearly 15 years, Nash embraced the freedom of working on his own music. "The truth is, after being totally immersed in me and David and Stephen and Neil's music, I'm done. I've had 10 years of it. Leave me the f--- alone. I need to concentrate on me now."

Still, no matter what Crosby might have done to provoke his ire, Nash admitted he still feels the loss of one of rock's more enduring partnerships — and signature vocal blends. "How can I not be sad?" he asked. "Look at the music we probably lost. How can I not be sad about that?"