Spalletti asked for a sabbatical, saying his departure from the club was the right decision after giving it everything he had.
"I no longer have the energy to be up to the standard of what people love so much, so I have to take two steps back and leave," Spalletti said in press conference on Saturday.
"I am not someone who changes idea easily and I decided to leave because I feel that I've given all I had."
Speculation over Spalletti's future was sparked after Napoli's title win last month, with club president Aurelio De Laurentiis claiming they had reached a resolution over dinner before the coach confirmed his decision on Monday.
"After the Scudetto victory, the President said to everyone things that I would've preferred he say directly to me first. Once we met up, we cleared the air in 15 minutes... I left that dinner with the president saying Napoli will have a great future," he added.
Spalletti who took charge of Napoli in 2021, was grateful for the moments the club and fans gave him but said he would be unable to repeat "that joy that the fans deserve", adding that despite the difficult decision he must respect it.
"I thank everyone I met in these two unforgettable years, a group of extraordinary players, a city with fans all over the world and all the children who hugged me and showed the future of the Azzurri.
"I like the idea of becoming an honorary citizen of Naples, of coming back here 10 years later and still being considered a friend to many.
"In the last few days I have realised how tough this decision is. I am leaving a squad that is strong in all aspects, that has the foundations to build on. The love that surrounds me gives me the strength to continue to accept this decision," he added.