The 30-year-old, who was part of the controversial France team that suffered a first-round exit from the 2010 World Cup, has revealed that he told his manager he wanted to move on after the competition.
"Sometimes you have to make a choice in your life and there was an approach from two big clubs, Inter Milan and Real Madrid, and I just had a chat about it with the boss," he said.
"After the World Cup, I'd told [Ferguson] that I wanted to go, but when I went to his house we talked a lot and in the end he didn't have to persuade me to stay because my heart wanted to stay."
The Frenchman, who went on to win the Premier League with the Red Devils last season, elaborated on his relationship with the United boss, describing him as a father figure to the players.
"I'm very close to Sir Alex and have a lot of respect for him, and a lot of respect for myself," he said. "It wasn't anything incredible, it was just normal.
"The boss has to be the boss, but he also has to look like he's the dad of everyone.
"I made the right choice and I'm so happy. It was an easy decision because, if I am honest, I knew I wanted to stay at this club and achieve more."
Manchester United will face an MLS All-Star side on Thursday as they continue their pre-season tour of the United States.