I’d heard vague stories about something like this:

WARREN BUFFETT, the 76-year-old American billionaire, has married his
long-time companion in a private ceremony in Omaha, Nebraska.

Mr Buffett, whose first wife, Susan Thomson Buffett, died of a stroke
in 2004, married Astrid Menks, aged 60, his companion of 29 years, in a
civil ceremony on Wednesday night at the home of his daughter, who is
also called Susan.
…

Mr Buffett, the chief executive of Berkshire Hathaway, who is known
as the Sage of Omaha for his ability to pick stocks for long-term
investing, has lived with Ms Menks since 1978, but he never divorced
his first wife, whom he married in 1952.

Mr Buffett lived apart from his first wife for the last 27
years of their marriage, after she moved to San Francisco in 1977.
However, the pair remained close, talked every day and visited each
other frequently. The first Mrs Buffett suggested that her husband and
Ms Menks live together when she left for San Francisco. Ms Menks moved
into Mr Buffett’s modest suburban home in 1978. Mr Buffett was first
introduced to her by his daughter, who used to sing in a French café
where Ms Menks was a waitress.

An earlier blog post I’d done on Buffett led to my getting an email from someone who claimed to know the domestic circle. Shocked allegations "He’s got a mistress!" and so on. I didn’t do anything about it, but not because I couldn’t confirm anything, of course.

Just that my reaction was, so, a billionaire’s got a mistress? This is news?

I’ve also no idea how many people already knew the story.