It's about a historical manga. My memory of it is really vague but what I do remember is that it's really short and the plot goes something like this: the FL was arranged to marry the king. King already has a lover. Eventually, FL got pregnant and gave birth. The king's lover got out of the picture. The king is trying to get close to the queen. Both ML and FL are like very chill or should I say Nonchalant. Pleased help
Is it https://www.mangago.me/read-manga/i_ll_divorce_you_gracefully/ ?
But here the ml is just a noble not a king so I am not sure since the plot is identical

So I think this one is like a one shot inserted in a series. You know how mangas usually have those unrelated one shots inserted out of the blue? Yeah, I think it's one of those or maybe it's part of an Anthology. Basically Uke finds a cat, Seme tells Uke that his parents arranged a marriage for him. Uke feels sad. Then Cat disappears, Uke tells Seme about it then says "everyone just end up leaving me alone." Seme looks for cat, founds it, then asks it to come home because uke is lonely. Then Seme tells uke that he turned down the arranged marriage