What was the sexual orientation of Laurence Olivier?

There is reason to believe he may have been bisexual - he was married, as I recall, three times and had a sexual relatrionship with each wife, but there is also biographical evidence of an ongoing sexual relationship with Danny Kaye.

In reading Noel Coward's diaries (and he was close friend during Olivier's marriage to Vivien leigh) I can recall no mention there of Olivier's homosexuality and I would expect it to have been mentioned by Coward if it was common knowledge.