looking for historical? josei romance (Solved)

[EchoGirl]

I believe it was charas with 'western names' (tho don't know if it was set in america or europe) and the female lead was aware that her romance interest was in love with his sickly younger sister (tho there was a scene where a 'rejected' male suitor had a brief convo with the lead and the male lead did seem to be irritated/subconsciously jealous)
but, she pretended she wasn't interested but still proposed a marriage of 'convenience' since she didn't wanna accept a diff marriage offer and he wouldn't have to be away from his sister, they all went to a diff place/sister joined them on their 'honeymoon', there was only like 5-6 chapters the last time i saw it

(may have been removed due to the DMCA series tho the series title couldn't find either)

 

[undeed]

the sickly younger sister part reminded me of this
but the honeymoon and jealous part reminded me of this, but it's not the [FMC's sickly little sister]

there was another "lover stolen by little sister" fantasy romance story similar to the first one, but I don't remember it very well

 

[EchoGirl]

the sickly younger sister part reminded me of this
but the honeymoon and jealous part reminded me of this, but it's not the [FMC's sickly little sister]

there was another "lover stolen by little sister" fantasy romance story similar to the first one, but I don't remember it very well

Yes Bystander is the one, thanks (lol other one sounds like it’d apply to multiple series since fantasy happens a lot with some Korean manhwa with like stepmothers and such tho I haven’t rly read those but I suppose those are more focused on the age gaps too)