Today, January 28, in many places the Emperor Charles the Great is commemorated liturgically. His canonisation was performed by an antipope (Paschal III, a creature of Barbarossa), and he is not in the Roman Martyrology, so he is nowadays tactfully celebrated as a Beatus. (I hope those with a devotion to him will forgive my cynicism when I remark that the article on him in Gueranger is rather amusing to read, as it attempts with angry indignation to rebut accusations that Charlemagne's matrimonial life was less than, er, canonical.)
And, in two days time, there will be those who commemorate blessed (note my cunningly lower-case b) Charles Stuart, who has had the word blessed attached to him liturgically by Anglicans since 1662 (the authorised texts, to the best of my knowledge, have never called him Saint).
That was during an age when Kings had mistresses as a natural adjunct of Royal Majesty. (I believe there was even one German king, a laudably uxorious chappy, who maintained a number of titular 'Mistresses', although he never laid a finger, or anything else, on any of them.)
But blessed (note my cunningly lower-case b) Charles was notorious for marital chastity. The Court Masques of his reign exalted the theme of chaste marital love. There are worse themes than this to incorporate into royal ...or any ... ideologies.
I think this blessed (note my cunningly lower-case b) is quite a good candidate for imitation in this age of ritual and government-encouraged promiscuity.
May blessed Charles the Royal Martyr pray for us all.
And, of course, may the unmartyred and matrimonially debated Blessed Charlemagne do the same.