Sir Alex Ferguson said he would have stayed on longer as Manchester United manager had it not been for the death of his sister-in-law.
"I definitely would have carried on," Ferguson told the Daily Telegraph.
"I saw Cathy was watching television one night, and she looked up at the ceiling. I knew she was isolated. Her and Bridget were twins, you know?"
Ferguson, who remains at United as a director, had planned to retire in 2002 but his wife convinced him to carry on. She did not try to persuade him to do the same in 2013, however.
Ferguson added: "But when I told her this time I was going to retire she had no objection whatsoever. I knew she wanted me to do it."
The 73-year-old shocked the football world in May 2013 when he announced his decision to stand down as United boss after 26 years in charge - having delivered the club's 20th top-flight league title and 37 other trophies.
David Moyes was appointed as Ferguson's successor but his reign lasted just 10 months before he was sacked in April last year as United failed to qualify for the Champions League for the first time since the 1995-96 season.
Dutchman Louis van Gaal was charged with the task of bringing the glory days back to Old Trafford when he took over after last year's World Cup, but Ferguson has revealed had it not been for the death of his wife Cathy's twin sister, Bridget Robertson, he could still be in the hot seat.