His partner is Lydia Lopokova, a celebrated ballerina, and Keynes' wife. Some history and gossip. (It's the Daily Mail, sorry.) Lopokova "danced with Nijinsky in St Petersburg, married a bigamist in New York, had an affair with Stravinsky in Spain and was instrumental in the development of British ballet."
Huh. I had thought that Keynes was gay. But the marriage seems to have worked, after a fashion. "Having seen Nijinsky and Massine switch their allegiances under assault by determined women, she took care to play down her femininity. One throwaway remark suggests that she even wore trousers in the bedroom."
Oh, to be a fly on the wall of the Keynes' boudoir!