Did Prince Philip Have an Affair with a Russian Ballerina as Implied in The Crown?

Spoilers ahead! The second season of The Crown wastes no time delving into the tensions in Queen Elizabeth and Prince Philip's marriage by the mid-1950s. Episode one centers around an implied affair between Philip and a world-famous dancer. Ahead of Philip's five-month tour aboard the royal yacht Britannia, the Queen hides a gift in her husband's briefcase and stumbles upon a photo of a beautiful ballerina -- Galina Ulanova. At the time, she doesn't confront Philip about the photograph, but late...