Ice Man Webtoon
Complete | Milla,Haedal | 2000 released
No Love Zone Webtoon
Complete | Danbi | 2019 released
K's secret
Complete | Morak | 2018 released
Main couple started out with the LI being extremely abusive: manipulative, controlling, coercive, even physical abuse at one point. It shifts to them being a pretty normal and healthy couple but the love interest is a walking red flag.
Hitorijime no Jouken