Diana did not initiate the adultery phase of her marriage, Charles did; she unfortunately descended to it after her husband's liason became more or less permanent and was thrown in her face by both Charles and Camilla. Nor did she boast of her ancestor's behavior as a rationale.
The double standard is alive on FR.
And no, the people's feelings not only have not mellowed, but the calls for the end of the British monarchy are regularly linked to the prospect of Charles and Camilla on the throne.
Well, I’m not a Brit; but I think there has long been a faction wanting to end the Monarchy, with not much to do with Charles.
I doubt it will happen anytime soon.