Anohito to Nitenai Kuchibiru

Collection of short stories:

1) Anohito to Nitenai Kuchibiru
Kaji was in love with his sempai for years but his sempai got married and had a child. Kaji takes care of the kid and watches him growing up...

2) Kuchibiru Kara Biyaku
Sequel to Anohito to Nitenai Kuchibiru

3) Blood
When their father dies, the rival half brothers must sort through their feelings of anger, regret, pain and desire that their lives have been steeped in thus far...

4) Kagari Oni
An exorcist solves a mystery involving demons. Not really a romance, just a historical fantasy story.

5) Datenshitachi no Yoru
S&M relationship between step siblings is taken to extremes.

6) Double Snake
A former gangster has turned into a regular office worker, but he still sleeps with his gangster lover. But one of the newbies doesn't like the fact that his favorite 'boss' is having a relationship with an office worker.