Musk is the richest person in the world, with an estimated fortune of $240 billion, and Brin ranks eighth worldwide, with $95 billion, according to the Bloomberg Billionaires Index. Brin and Musk, among the nation’s most famous entrepreneurs, were longtime friends. Musk has said that for years he regularly crashed at Brin’s house in Silicon Valley.

Brin provided Musk with about $500,000 for Tesla during the 2008 financial crisis, when the company was struggling to increase production. In 2015, Musk gave Brin one of Tesla’s first all-electric sport-utility vehicles.

In recent months, there has been growing tension between the two men and their teams, according to the people familiar with the matter. Brin has ordered his financial advisers to sell his personal investments in Musk’s companies, some of those people said. It couldn’t be learned how large those investments are, or whether there have been any sales.

Brin filed for divorce from Nicole Shanahan in January of this year, citing “irreconcilable differences,” according to records filed in Santa Clara County Superior Court. The divorce filing was made several weeks after Brin learned of the brief affair, those people said.

Sources: https://www.marketwatch.com/story/elon-musks-alleged-affair-with-sergey-brins-wife-led-to-falling-out-between-billionaires-11658693528#:~:text=Elon%20Musk%20engaged%20in%20a,people%20familiar%20with%20the%20matter.