The 54-year-old, who coached Murray to the 2012 US Open and 2013 Wimbledon crowns after he had lost all four of his previous Grand Slam finals, ended one of tennis's most effective partnerships over dinner in March.
Beyond a terse statement in which he talked of working on some of his "own projects" and playing on the champions tour, Lendl had steadfastly declined to elaborate on the break-up.
Just before the US Open, however, where Murray will bid for his third Grand Slam title under the guidance of Frenchwoman Amelie Mauresmo, Lendl revealed changes in his personal life had cut the time available to spend with his former client.
"It was lots of little things combined. Like playing more on the vets tour, and one of my daughters returned home," the eight-times Grand Slam champion told British media at Flushing Meadows.
"The youngest one is 16 and she had been away at horse riding school and but now she has come back to live with us.
"My mum is now 79 and lives in Prague, I need to go more to the Czech Republic than I used to.
"The planes are a pain in the arse. The places, the hotels - England was good, Australia was good, here it was alright. It was the smaller trips I didn't like.
"All these things combined. And you know with Andy, after his surgery and after winning Wimbledon and all that, I felt that if anything he needed more time rather than less time."
Initially considered an odd-couple pairing, Lendl guided Murray to an Olympic gold medal for Team GB at the London Games, one highlight of a glittering year featuring his first grand slam title at Flushing Meadows and second at Wimbledon 10 months later.
The latter ended Britain's 77-year wait for a men's champion at the home Grand Slam, triggering a huge outpouring of emotion.
Asked whether the difficulty of matching the exhilaration of the period had played a part in his decision, Lendl said:
"Yeah, and that too.
"Everyone is different, and when you win a big tournament like Wimbledon, it' not easy sometimes," added Lendl, who famously never won the tournament.
"Some people find it more difficult than others, and I'm glad Andy found Amelie (Mauresmo) who can give him the time he needs."
Lendl travelled to Flushing Meadows at the weekend from his home in Connecticut to catch up with Murray for the first time since their break-up dinner in Miami.
The Czech-born great said Mauresmo should rely heavily on Murray's friend and assistant coach Dani Vallverdu.
"You guys don' understand how much I relied on Dani, and I hope Amelie relies on Dani as well," he said.
"Many times he would come to me and say: 'hey, you need to stop the practice' And I would say: 'What? Andy looks fine to me'. And Dani would say: 'No, he's done'. And two or three minutes later, he was done. So you get that two or three times and you start listening much better."
Having largely steered clear of tennis for nearly two decades before joining Murray's team, Lendl held out the possibility of returning to the player's box again.
"Maybe eventually but it has to fit right," he said.
"It wouldn't have worked if Andy had called me two years earlier, or if he had called me two years later.
"And it has to be someone I feel I can offer something to. If it was John Isner, for example, I am not going to be able to tell him how to hit a serve."
Murray, seeded eighth, opens his US Open against Dutchman Robin Haase on Monday.
Watch the US Open live on British Eurosport.
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