Dan Carter was ready to quit rugby just 15 months out from this year's World Cup triumph and credits his wife Honor for keeping him in the game.
And he has also revealed his dissatisfaction at playing second five-eighth for the Crusaders this year.
Carter, who is set to make his debut for his new French club Racing 92 this weekend, says he was set to step away from the rugby after breaking his leg, having re-built his career following a sabbatical.
"It was clear that I was at a place where I had neither the health or the form to be part of it," Carter has written on Players' Tribune, the site set up by American sporting superstars Derek Jeter and Kobe Bryant.
"For the first time in my live I began to question my love for the sport. I questioned whether my body could handle it anymore.
"The critics who had been going on about my age started making more sense to me.
"All those big plays I'd made during my career seemed like memories now. And I wondered what kind of legacy I'd leave behind.
"I was fortunate to have a wife who played hockey for New Zealand, and had a deep understanding of my personal feelings as well the psychology of sports.
"I would tell her that I wanted to retire, that I didn't think I had the talent anymore. She was my rock...and despite my arguments, kept encouraging me. If it wasn't for her and my love for the All Black jersey, I'd probably have long since hung up my cleats."
Carter retired from international rugby after kicking 19 points in the World Cup final victory over Australia. A few days later he was named World Rugby player of the year for a third time.
In the piece, clearly written with an American audience in mind, Carter said he would be confident one day, and contemplating how to retire the next. Things only clicked into place on the eve of the World Cup, when he turned in a top display as the All Blacks crushed Australia at Eden Park in his final test on home soil.
Carter said his move from first five-eighth to the No 12 jersey for the Crusaders this year was "tough".
"After some wavering, my provincial team decided to re-sign me," he said.
"They played me out of position for most of the season, which was tough because I was trying to prove I could still be a fly-half for the All Blacks.
"Once we made it halfway through the season and I was injury free...I shifted my focus to elevating my play to another level and making meaningful contributions."
