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.
Can this be it?
https://www.mangago.me/read-manga/muri_marriage/
I was angry at the first chapters, crying almost at the end, en happy crying at the ending. I did not know I was gonna like this story that much. Also hope the “dad” dies painfully, worst than he thinks its gonna be.