The French full-back spent last season on loan from the Ligue 1 club with the deal including an option for the Blues to pay the World Cup winner for £13.5m.
"I had a proposal to extend my stay in Everton. But staying there wasn't just up to me," he told Journal L'Est Éclair.
“The two clubs discussed it and couldn't come to an agreement.
“In this case, there is nothing we can do about it; it's the football club that received other concrete proposals, from English, German and Spanish clubs, which didn't meet my expectations.
“So I preferred to play it safe and go home to Monaco, to a club with which I've had a lot of success."
Sidibe, 28, is back with AS Monaco but says he would like to return to the Premier League.
“When I left for there, I just wanted to gain experience, to discover a new football," he said.
“I joined a team whose captain, an emblematic player, played in my position.
“However, I was able to find my place, to play between 25 and 30 matches during the season, being good, performing well, with good statistics. This championship breathes football, the stadiums and the fans are fantastic. I also had the chance to rub shoulders with Carlo Ancelotti, a world-renowned coach.
“Yes, I will only have good memories of my time in Everton. I can't wait to return to England in the very near future."