"It is all about them. I love my boys," John told ET. "I hate being away from them, and I've had so many wonderful memories from touring. I have done over 4,000 shows, and I love performing, but I love my sons more."
John said that he had no problem bringing them on tour when they were younger, but Zachary, 7, and Elijah, 5, now have school to consider.
"When they were younger, we took them everywhere because they were portable," he said of his boys, whom he shares with husband David Furnish. "And then, of course, when they start proper school, they have a schedule. And they sat down and showed me the curriculum, and I said, 'What are we going to do in the future? When is this going to stop?' And I said, 'I really want to stop.'"
As expected, "stopping" for Elton John will be anything but mundane. Before officially retiring, he'll embark on a three-year worldwide tour he's dubbed the "Farewell Yellow Brick Road Tour," which he promised will be spectacular.
"I probably do 120 shows a year, and so this is the last hurrah, and to do that, you have to go around and say to all the continents, 'This is it. Goodbye. Thank you very much,'" he explained. "I want you to see the best show I've ever done, the most fantastic show I've ever put on as far as visually and the content. We thought a lot about it."
John also revealed that he had been thinking about retiring since 2015 and has been planning his last hurrah tour for the past18 months. Tickets will go on sale for the North American portion of the tour on Feb. 2, with shows beginning in September.
Until he hits the road, the "Rocket Man" singer has got plenty on his plate. John and his longtime writing partner, Bernie Taupin, will receive the Recording Academy President's Merit Award on Sunday at the GRAMMY Awards, where the iconic songwriter will also be performing with Miley Cyrus.
John told ET that he draws inspiration from younger artists like Cyrus, also calling out Sam Smith, Ed Sheran, Kesha, SZA, Lady Gaga and Eminiem as having been "thrilling" to get to know and collaborate with.
"It is so inspiring to work with people who are so talented. When I met and worked with Eminem, when I first rehearsed with him, I just was gobsmacked by his incredible stage performance, and I got goosebumps. It was like watching an early Mick Jagger," he said. "Same with Gaga, same with Ed Sheeran. I love working with younger people. It is thrilling and it keeps me happy... I love it."
But for all the thrills, John says that his farewell tour will be just that: farewell. No holograms, no more touring outside of England, no suddenly coming out of retirement for one last tour.
"I'll be 73, 74 by [the end of the farewell tour,] and this is a different point of my life," he said. "I've had this fantastic life. My boys are far more exciting to me than going out abroad and playing a show."