Kurui ~Ryoujoku Kyoushitsu~

Our hero, Yosuke has become an expressionless being caused by the loss of his girlfriend from childhood, Yuki Hinata, who committed suicide. Yosuke enrolls in the university he and Yuki had planned on enrolling in together. Unfortunately, Yosuke's wounded heart never recovers; his condition worsens to the point of him becoming a total recluse. He begins having counseling sessions with a young assistant professor named Kasumi. Even with these sessions, Yosuke does not recover. Yosuke and Kasumi gradually become intimate; without realizing it, they become bound in a physical relationship. For Yosuke, this relationship is nothing more than an instrument to satisfy his lustful desires. Losing himself in these day-to-day carnal pleasures, Yosuke has become enchanted with a reoccurring nightmare...

[From gamelexgs]