lucia is that you?

I dont think theyre too alike, maybe because they're both set in situations of contract marriages, in old times with nobles, dukes, barons, and theres church stuff

I can see what you mean: old fiance was abusive trash, new love interest is a tall black haired beast on the battlefield. But I feel like the characters themselves are the main difference. In lucia the duke is cold, controlling, and possessive of lucia to an unhealthy extent. He's kind of a terrible person even while still having his wife and would definitely be a terrifying man to be married to. Lucia is also much less involved, she handles political with the other woman and is polite and smart but in terms of plot what she actually does isn't a lot.
Where as with the characters in this, the male lead seems much more supportive and gentle, he cares about her and would probably kill for her, but also won't lock her down into the house to keep anyone else from even looking at her and doesn't feel the need to limit her activity/wardrobe so no other man will see her. Even the female lead is more involved, she has a bit more agency in this story and also does more in the plot. Maybe that will change but for now I'd say this couple feels more stable and caring and verbally positive. I know you probably weren't expecting a full response like this but. TL;DR I can understand what you're saying, it makes sense since the characters and base storyline have similarities.

I keep thinking it is the Duchess tea recipes one