Earlier this year, after Musk had an affair with Nicole Shanahan, the couple filed for divorce, citing "irreconcilable differences."
In the aftermath of Musk's split from former girlfriend Claire Boucher, Brin and Shanahan had an affair at Miami's high-profile Art Basel event.
While Musk tries to exit his $44 billion deal to buy Twitter, his personal life is never far from his business.
It was reported earlier this month that Musk had twins with Shivon Zillis, a former Tesla employee and top executive at Neuralink.
According to the victim, Musk asked her for a massage, exposed himself, and offered her sex. SpaceX paid her $250,000 to keep quiet.
In contrast, Brin was once called "the Google playboy" for his sexual engagement with employees, according to HR manager Heather Cairns.
In a Vanity Fair 2014 report, Brin revealed Rosenberg was still married to 23 and Me co-founder Anne Wojcicki, who was dating another Google executive.
Brin offered Tesla $500,000 in funding in 2008, which Musk returned two years later with the Model X.
Brin told advisers he would sell his personal investments in Musk after Musk went on one knee and asked for forgiveness at a party earlier this year.