New AC Milan defender Leonardo Bonucci said being left in the stands for Juventus' Champions League meeting with Porto finally convinced him he had to leave Turin.
Bonucci and coach Massimiliano Allegri were involved in a heated exchange toward the end of a Serie A match with Palermo and the defender was then left in the stands for the Champions League round-of-16 first leg.
The Italy international said afterwards that there were no hard feelings over the incident, but he has now acknowledged that it was a factor in his decision to move on.
"People thought that was the most striking thing, but in truth it was just the final straw," he said, in quotes translated by Football Italia. "There had been other situations before that."
He added: "In the last part of the season the link faded on both sides and we decided to move apart. Something crumbled in recent months, and this change was the consequence of that. To give 100 percent, I need to feel important, something that at Juventus was recently happening only in fits and starts.
"I couldn't go with that. Even the most beautiful marriages sometimes end. I gave Juve so much and they gave me so much. It wasn't an easy choice for me, because seven years are difficult to close off and forget.
"The rapport had come to an end though, neither party wanted to continue together. I have to say, though, that given how it ended we came out well: myself, Juve and Milan."
Former Inter Milan defender Bonucci, who won six Serie A titles at Juve, warned Bianconeri fans against viewing him as a traitor.
He said: "Given what I gave to Juve, I don't feel like a traitor or a mercenary. If they whistle me, they ought to know that, just like the insults I received at Juventus Stadium fired me up, it'll be the same if they jeer me."
He acknowledged that it would be "strange" to wear the Milan shirt given his history but is determined to help the club rise back to the top after a hugely impressive summer in the transfer market in which they have spent €200 million on 10 new players.
"I want to make this club great, along with my teammates," he said. "Milan deserve better in both Italy and in Europe: in a nutshell they deserve to climb back up.
"The club has made big investments on the transfer market thanks to the long-term vision of [general manager Marco] Fassone and [sporting director Massimiliano] Mirabelli. Now it's up to us to increase the fans' enthusiasm with wins."
Milan finished sixth in Serie A last season, securing Europa League qualification.