Can this be it?
https://www.mangago.zone/read-manga/muri_marriage/
No, it was older than this story and it was an one-shot story. And It was kinda dark. Not sweet but thank you for trying .
Oh goodness I found it, it is not good but I'm so glad I found it It is called Aibu (yaoi) and its the first ch. I definitely altered how it looked to me lol
Wow, that took some time! I'm glad you found it. (As for the one I sent.. I thought I attached a link to a different one :") Still wasn't this one ahha)
Good job!
This is a long shot. But a looong time ago I read a oneshot manga where I think Uke wakes up in a room or before getting to the room (Japanese style) of a yakuza leader being told he will be his partner from now own. There is some bdsm involved. I think it was a one shot attached like an extra to another main story not related to it. I remember the last page was the Seme and uke (who accepted his role) walking with kimono looking like a freaking portrain and the yakuza goons beside them. If this ring a bell let me know.