is it this one? https://www.mangago.zone/read-manga/doronuma/
I think it's one Hadakeru Kaibutsu
https://www.mangago.zone/read-manga/sabita_yoru_demo_koi_wa_sasayaku/
This is the one you're looking for, I believe? The abusive lovers' story is this:
https://www.mangago.zone/read-manga/hadakeru_kaibutsu/
The comments are saying there's more manga in the series. I'm not too sure about the particular order, but the top 5 comments on both manga are very helpful in making a timeline.
Thank you!!!
No but that one horrified me too
So it’s pretty toxic. There are two stories I believe. UKE (once top) was an abusive boyfriend to his ex, UKE struggled at work and was abused at work, so he took it out on his living ex. Eventually they broke up.
UKE’s ex got a new bf and they have their own story. UKE is miserable, and he also meets his own bf and he becomes the bottom. UKE becomes happy at the end.