Afghanistan, Nov. 15 -- A Reddit joke has made Meta chief executive Mark Zuckerberg the internet's "last faithful billionaire," as the fallout from Nvidia founder Jensen Huang's affair spreads online.

On Thursday, the same day Nvidia announced Huang's resignation, a user in the r/NvidiaStock forum posted a photo of Zuckerberg walking beside his wife, Priscilla Chan. The caption read: "Surprisingly, the only billionaire who is still faithful to his wife." The post drew thousands of reactions, and outlets have since called him the "last faithful billionaire standing."

Some users said Zuckerberg was too absorbed in technology to stray. Others pointed out that nobody knows what goes on inside a marriage.

Behind the joke is a serious story. O...