now fully radicalised (though he is right about architecture) https://twitter.com/AyoCaesar/status/1328474631301435395

Did Charles think that he could just hold on to his official mistress and also be legit married? As royal men of the past used to do, building their mistresses lovely houses and bringing them to court etc. Except that's not what either Diana or the public thought was happening.

The whole of The Crown is about the royal family contending (badly) with modernity, and that includes changing marriage norms.

Eli J. Finkel describes three eras of marriage:

Institutional marriage, pre-1850 – marriage is an economic arrangement for the purpose of childbearing

Companionate marriage, 1950-1965 – marriage is for childbearing but should involve love

Self-expressive marriage, 1965 to now

The Crown represents the Queen and Philip's marriage as companionate, but was Charles angling for an institutional marriage, while Diana was expecting a self-expressive one?

Of course royal self-expressive marriages have a failure rate approaching 100%. No divorces in the royal family until 1978 and then all but one of the Queen's children have been divorced. Companionate probably a more achievable model.

This is a great article by Finkel on the make-or-break nature of self-expressive marriages https://www.nytimes.com/2014/02/15/opinion/sunday/the-all-or-nothing-marriage.html