I had an economics professor in college that described Keynes as a wild socialite that would attend multi day parties and anything goes orgies. According to her he begrudgingly decided to save capitalism in order to preserve his party life style. I'm sure this is largely hyperbole and just a funny story, but is there a kernel of truth to it?
Keynes was a core member of the Bloomsbury group, which was renowned for its parties and for its laissez faire attitude to sexuality, including extra-marital and homosexual affairs. They often courted controversy so it's difficult to untangle truth from exaggeration or fiction, but it's safe to say that Keynes' membership shows his lifestyle and opinions were sufficiently radical, by the standards of the day, for him to have been deemed worthy of membership.
From the literature I've read he was quite the socialite. Most descriptions of him state that he simply enjoyed being with people, not that he felt he needed to "save capitalism". He was described simply as an eternal optimist that loved spending time with interesting people.
His works in economics came about because he was brilliantly gifted in both mathmatics and economics and had seen what happened to the world under the Great Depression.