- http://www.mangago.me/read-manga/nanadome_no_gomenne/
Nothing really compares though, the ending to an Uncomfortable truth was fitting and terribly sad.
I guess also, the detective & Sealwoo would fit the decription of killing and committing other crimes due to their love for each other. (does that make sense?). All of the chapters haven't been translated, but basically Sealwoo regarded the detective as being his "light", due to childhood trauma where the detective saved him. It ends with Sealwoo, alone and restrained in a hospital/prison so quite sad and similar to an uncomfortable truth.
http://www.mangago.me/read-manga/my_blood_and_soul_to_you/
Looking for manwhas/mangas that has a similar plot like An Unforgettable Truth? Where a girl/guy is overly obsessed with his/her family member in either romantic or non romantic way to the extent they (could) kill people for them? Shoujo, Yuri, or Yaoi any type of romance is gucci too