The Tesla CEO, 50, confirmed the news in a statement on Friday.
"We are semi-separated but still love each other, see each other frequently, and are on great terms," Musk told Page Six.
"It’s mostly that my work at SpaceX and Tesla requires me to be primarily in Texas or traveling overseas and her work is primarily in LA. She’s staying with me now and Baby X is in the adjacent room."
Grimes and Elon Musk attend "Heavenly Bodies: Fashion & the Catholic Imagination", the 2018 Costume Institute Benefit at Metropolitan Museum of Art on May 7, 2018 in New York City. (Photo by Taylor Hill/Getty Images)
Musk and Grimes, whose real name is Claire Elise Boucher, started dating in 2018 and share a one-year-old son together named X Æ A-Xii.
The pair was last seen together at the 2021 Met Gala in New York City. Grimes, 33, walked the red carpet solo and met up with Musk later inside the event. After the fashion party, they threw a star-studded afterparty at the private club Zero Bond.
Musk was previously married to author Justine Wilson from 2000–2008 and they share twin sons Griffin and Xavier, 17, and triplet sons Damian, Saxon and Kai, 15. They also had a sixth son, Nevada, who died at just 10 weeks old.
After Wilson, Musk married and divorced actress Talulah Riley twice. The first time 2010–2012 and then again from 2013–2016.
Meanwhile, Grimes was in a relationship with electronic musician Jaime Brooks from 2012–2018.