Graham Nash said a series of things led to his recent estrangement from longtime musical partner David Crosby, one that has essentially ended Crosby, Stills & Nash.

First there was the struggle to complete a never-released covers album produced by Rick Rubin in 2010. Attempting to keep that failed project on track "felt like the myth of Sisyphus, pushing a big rock up a hill, and it's slipping back," Nash told Rolling Stone. "And I ran out of patience with it all."

A few years later, Crosby clashed with another occasional collaborator, Neil Young, over Young's new girlfriend, and then with Nash over Nash's 2013 autobiography. "My relationship with David began to sour," Nash said. "We used to be on the same page, but not anymore."

A collaboration that had led to so much success with CSN, as well as with Crosby, Stills, Nash & Young and as a duo, seemed to have crash landed. Nash began work on a solo record, This Path Tonight, which came out earlier this year.

Nash said he emerged with a new perspective after taking some time to "really absorb what I had done with my life. ... What I thought were the happiest parts, in fact, weren't. I said, 'Look, how much longer is my life going on? I can just settle and coast through it, or I'll follow what my heart said I should be doing.'"

Young has since hinted that he might consider new work with CSNY, and Nash won't rule it out either. "He's right -- you never know," Nash admitted. "There have been times when I've been so pissed at us all for wasting time and not getting on with the job that I wouldn't talk to any of them. But if Crosby came and played me four songs that knocked me on my ass, what the f--- am I supposed to do as a musician, no matter how pissed we are at each other?"

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