The world number three won gold at this year's London Olympics and then broke his Grand Slam duck at the US Open under the tutelage of the Czech trainer.
Murray and Lendl paired up at the beginning of the year and the Scot sees their partnership remaining intact for some time to come.
"Ivan and I have a very good relationship, it's very honest and open, that's why it has worked so well and why both of us are planning long term," the British number one said.
"We spoke at the end of last year and it was much more short term - 'let's see how the first few months of the season go'. Now it's, 'What are we going to be doing in four or five years' time?"'
Murray, 25, added that winning the Olympic tennis tournament at the All England Club in the summer represented a turning point for him.
"Since the Olympics I just feel a bit better about myself," he said. "I find it easier to walk around with my head up, whereas before I was always head down, not wanting anyone to see me or say anything.
"Maybe I felt that having lost in Grand Slam finals I was letting whoever it was down.
"I know I had been reminded every day for the last six years that it's this long since someone from our country won a slam. So there was part of me probably that felt a little bit of responsibility.
"It's nice not to have worry about that anymore and see what else I can achieve."