Musk, 50, confirmed his breakup with the "Alter Ego" judge, 33, in a statement last month.
"We are semi-separated but still love each other, see each other frequently, and are on great terms," Musk told Page Six.
The former couple met in April 2018 via Twitter after they traded quips about Rococo Basilisk and artificial intelligence.
"Elon was researching the idea of joking about Rococo Basilisk, and when he saw that Grimes — whose real name is Claire Elise Boucher — had already joked about it, he reached out to her," a source later told Page Six. "Grimes said this was the first time in three years that anyone understood the joke. They were both poking fun at AI."
The pair made their debut at the 2018 Met Gala when the Canadian singer donned a black and white ensemble to adhere to the "Heavenly Bodies: Fashion and the Catholic Imagination" theme while Musk wore a simple white blazer over black trousers.
However, many soon believed trouble to be brewing in their new romance when they unfollowed each other on social media in August 2018 before hitting the follow button on each other again, a pattern that would repeat during their relationship.
Here's a look back at their romance:
Grimes said in an interview with the Wall Street Journal that Musk is a "super-interesting god---n person," before adding that she loves him. In an email to the publication, Musk returned the compliment.
"I love c’s wild fae artistic creativity and hyperintense work ethic," he said.
Grimes took to Instagram to reveal she was pregnant with the couple’s first child. The image showed a nude Grimes with a baby superimposed on her belly.
The same month, Grimes and Musk each unfollowed the other on Twitter again.
Grimes and Musk welcomed a baby boy named X Æ A-12.
"Mom & Baby all good," Musk tweeted at the time.
Shortly after confirming the name, Musk replied to a fan who asked to see a photo of their baby boy, and he obliged.
"A pic of you holding the baby would break the internet ... " said another fan. "please share one."
Like clockwork, Musk promptly shared another image.
Following a back-and-forth Twitter exchange in which Grimes’ mother publicly called out Musk for tweets he made about taking the "red pill," Musk and Grimes unfollowed each other again.
"I love you but please turn off ur phone or give me a [c]all," Grimes tweeted. "I cannot support hate. Please stop this. I know this isn’t your heart."
She went on to delete the tweet.
In an interview given to the New York Times, Musk admitted that he hasn’t done much in the early stages of his son’s life.
"Well, babies are just eating and pooping machines, you know?" he said. "Right now, there’s not much I can do. Grimes has a much bigger role than me right now. When the kid gets older, there will be more of a role for me."
In early May, Musk took his shot at hosting "Saturday Night Live" and garnered rave reviews for his showing.
Grimes even got in on the mix, and Musk was also accompanied by his mother, model Maye Musk.
Four months later, Grimes opened up her life to Vogue cameras ahead of the 2021 Met Gala and revealed to the world that she doesn’t "identify" with the word "mom" and that her son "can sense [her] distaste for the word."
"I think having a baby was a big rebirth for me, like artistically," said Grimes. "Being a mother feels weird to say. For some reason, I don't identify with that word."
"Which is also really weird because X, he says 'Claire,' but he doesn't say 'mama.' Which is so ... I'm like, "How are you...?'" she continued. "Like, maybe he can sense my distaste for the word 'mother.'"
The same month, it was revealed that Musk and Grimes had ended their relationship. However, Grimes said in a social media post that she is still living with the Boring Company boss despite their split.