Elon Musk and Grimes are calling it quits ... they've broken up after 3 years of dating.
The SpaceX and Tesla honcho says he's "semi-separated" from Grimes ... though he says they are still on good terms and are co-parenting their 1-year-old son, the famously named, X Æ A-Xii Musk.
Elon reportedly told Page Six he and the Canadian singer still love each other and they are all living under the same roof, albeit in different rooms.
The former couple made a public appearance together at the Met Gala earlier this month, as well as back in 2018. It's unclear what exactly led to the split.
It's possible their careers are getting in the way -- Elon's busy running tech empire, which requires lots of travel to Texas and Europe, and Grimes is working in L.A. as a judge on the new FOX show, "Alter Ego."
As we reported ... Grimes gave birth to their baby boy in May 2020.
Elon's adding to a list of famous exes ... which include his first wife, author Justine Wilson, 2 marriages to "Westworld" star Talulah Riley and Johnny Depp's ex, Amber Heard.