Bill Gates was on the verge of tears as he admitted "messing up" his marriage of 27 years to former wife Melinda French Gates during an annual exclusive camp for billionaires.

According to one of the attendees, Gates "fessed up" that the divorce with Melinda was his fault.

Another attendee described the Q&A, which was hosted by CNBC's Becky Quick, at the Allen & Co. conference in Sun Valley, Idaho, last week as "very moving."

However, a different source was frustrated that Gates refused to communicate with other attendees.

"Bill Gates was pretty much a total asshole" the attendee was quoted by the New York Post as saying.

In the Q&A, the 65-year old Gates did not refer to an "affair" as the reason for the divorce, Daily Mail said.

Gates made the comments after arriving at the conference late to attend an exclusive dinner hosted by former Allen & Co. President Herb Allen.

Other billionaires including Jeff Bezos, Mark Zuckerberg and Sheryl Sandberg attended the camp, sources said.

Gates was seen walking and talking with Zuckerberg. He was also spotted by a paparazzo taking a walk with Evan Greenberg, president and chief executive of insurance company Chubb Limited, Variety said.

Gates, who is worth $130 billion according to Forbes, stepped down as Microsoft chief executive in 2014 but has attended the conference in the past.

After the divorce was announced, it was learned Gates had an "inappropriate" sexual relationship with a female employee in 2000 when he was still Microsoft CEO.

Gates resigned while an investigation into the relationship was being investigated by the Microsoft board.

Meanwhile, Gates' ex-wife was seen at private club Zero Bond last week surrounded by six bodyguards and three black sport utility vehicles.

According to a veteran of the celebrity scene, the size Gates' security detail is usually "reserved only for people in the top levels of government, or former presidents," Page Six reported.