"We went and had dinner," Murray told reporters ahead of the tournament. "We chatted for an hour about other stuff, and then we chatted about us moving forward."
The decision was not prompted by Murray's three-set loss to Milos Raonic at Indian Wells, he added.
"That wasn't something that happened after Indian Wells. We planned to sit down when I got to Miami to discuss moving forward," he said.
"It wasn't going to happen."
Murray credited Lendl with helping him mentally, particuarly with big matches and closing players out.
"He made a huge difference to my tennis," said Murray. "The thing that he was brought in to do was to help me get over the line in the big events, and that's what he did.
"So very hard person to replace, you know. You can't replace that sort of experience easily."
Lendl was not at Murray's last two events in Acapulco and Indian Wells, with the No. 6 experiencing three-set losses in both events.
In an earlier statement announcing that the two would no longer be working together, it was implied that Lendl no longer wanted to make a sufficient time commitment.
"Having helped him achieve his goal of winning major titles, I feel like it is time for me to concentrate on some of my own projects moving forward, including playing more events," Lendl was quoted as saying.
The statement pointed out that Lendl had been involved in his own academy and recently giving clinics as well as playing exhibition events in Kansas City, Oklahoma City, Nashville, Charlotte, and London, England.
Murray said he would look to find a replacement but would take his time.
"It's not going to change drastically the next few weeks," he said. "But I'm finished with Davis Cup, then I will sit down and have a think what I want to do with that situation and how I want to move forward with it.
"I think in the long term it's better to have, you know, someone there and having a structure and a plan as to how you're going to move forward and how you're going to improve.''