He recalled to the Telegraph: "My friends, my family, even my agent told me to leave after last year's Europa League final.
"But I felt the push of the club, from an emotional point of view, and I turned down also a very convenient offer from Saudi Arabia to stay at Roma."
Mourinho also said: "I still have a long career ahead of me. I'm 61, it's not like I'll finish at 65... It's not a question of the club: the only thing I want is for the objectives to be defined by everyone in good time I can't go to a club where, just because of my history, the goal is to win a title.
"The only thing I want is for that to be clear."
On United, he said: "I had a good relationship with the club from a personal point of view, but from a professional point of view it wasn't the best. I know who I am, I'm a football man. And when I was at Manchester United there wasn't all the material that ten Hag had at his disposal, I didn't have this type of support from the club, I didn't have this level of trust.
"So I left very sad because I felt that we were only at the beginning of a growth process. I'm sure that if they had trusted me at times and believed in my experience things would have been different. Even today there are a couple of players that I didn't want 5-6 years ago because for me they didn't represent the ideal profile to play in a club of a certain size."