Entertainment Music Grimes Says She and Elon Musk Have 'Broken Up Again' — but Notes 'We're Very Fluid' Grimes also revealed that she and Elon Musk welcomed a second baby, daughter Exa Dark Sideræl, in December By Rachel DeSantis Updated on March 10, 2022 11:45 AM Share Tweet Pin Email Grimes and Elon Musk may not have the most traditional of relationships, but their romance is still going strong. Though Grimes, 33, revealed in a new interview that she considers the SpaceX founder, 50, her boyfriend, despite Musk saying in September that the two were "semi-separated, but still love each other," she's since clarified that the pair have split again. "There's no real word for it. I would probably refer to him as my boyfriend, but we're very fluid," she explained in a Vanity Fair cover story. "We live in separate houses. We're best friends. We see each other all the time… We just have our own thing going on, and I don't expect other people to understand it." Grimes later amended her stance, posting on Twitter Thursday that, "Me and E have broken up *again* since the writing of this article haha, but he's my best friend and the love of my life, and my life and art are forever dedicated to The Mission now." For more on Elon Musk and Grimes, listen below to our daily podcast on PEOPLE Every Day. Elon Musk Has Been Telling Grimes He Wants to Leave for Mars 'Since Before She Was Pregnant' Grimes and Elon Musk. Taylor Hill/Getty The "Oblivion" singer said the former couple — who share son X and daughter Y — also want at least one or two more children. "This is the best it's ever been," she said of their relationship. "We just need to be free." Musk, who is the wealthiest person in the world, agreed, telling the outlet that them living in separate houses is for the best, as he is "reasonably neat" and doesn't "like things to be messy and anime." Elon Musk and Grimes Welcome Second Baby Together, Daughter Exa Dark Sideræl The pair first connected on Twitter in 2018, and made their debut as a couple at that year's Met Gala. They welcomed son X Æ A-12 in May 2020, and Grimes revealed in the interview that a baby girl named Exa Dark Sideræl (whom they call Y) was born to the couple via surrogate in December. Grimes (whose real name is Claire Boucher) is currently preparing for the release of her next album Book 1, which she explained is partly inspired by repeated talks she and Musk have had about her being a simulation, as they both feel as though she is extraordinarily well-suited to him. Elon Musk with son X. Theo Wargo/Getty "We keep having this conversation where E's like, 'Are you real? Or are we living in my memory, and you're like a synthesized companion that was created to be my companion here?'" she said. "The degree to which I feel engineered to have been this, like, perfect companion is crazy. Even just studying astrophysics and neuroscience. And it's really annoying because people think I'm an airhead who went to art school." In that vein, Grimes said that having much of the world learn who she was not through her music but through her relationship was difficult. "It killed me at first," she told Vanity Fair. "I spent 10 years f—ing producing, writing, engineering, every single f—ing thing on my own. And I f—ing proved myself." Singer Grimes Says She Loves Elon Musk: He's a 'Super-Interesting' Person Grimes and Elon Musk. Jesse Grant/Getty; Pascal Le Segretain/Getty Added friend Liv Boeree: "It frustrates me because she's as brilliant as him. When I see her referred to as the significant other of another person, it's like, Oh, come on." Though Musk said in September that their separation was largely due to the fact that she was in Los Angeles with their son and he was in Texas working with SpaceX and Tesla, Grimes has since relocated to Austin, moving in December after their daughter's birth. The billionaire, who was married three times — twice to Talulah Riley — has five sons from a previous marriage. His first son, Nevada, died of SIDS at 10 weeks old in 2002.