I'm actually looking for two separate things

1. Forbidden romances that don't get their happy ending.
   e.g. Hana no Miyako de and the last story from Hybrid Child

2. Tragic and twisted love stories à la Ogawa Chise, Nanadome no Gomenne and Sora o Daite Oyasumi. It doesn't have to include incest, just the kind of love that is utterly repulsive, yet strangely fascinating at the same time.

Bonus points if the art isn't full of yaoi anatomy.
Thanks a lot!