Yes, back to the Chick Flick genre. I wouldn't mention it, other than my compulsive need to log in every new movie I sit through. This barely qualifies, since Mrs. Salad is pretty sure I slept through large swatches. But, if you're a woman, you might like it.
Keira Knightley plays Georgiana Cavendish, Duchess of Devonshire (1757-1806). She's placed into a loveless marriage with the older Duke, played by Ralph Fiennes; her main duty, as far as he's concerned, is to produce a male heir. He's much more attracted to his mistress, and she has a lover on the side as well. She's also outspoken, controversial, a gambler, a drunk, … Basically, it's a Lifetime movie set in the English past.
All that may remind you of a more recent British couple. It's supposed to. And it turns out that Georgiana is actually an ancestor of Princess Diana.
Other than the melodrama, there are a lot of glorious costumes and fabulous settings, on which one can feast one's eyes, if one's eyes are hungry for that sort of thing. Mine pretty much aren't.