Kanojo no Shin'yuu ni Karada de Yuuwaku Sareru Himitsu no Kankei

The protagonist, Sakanoue Yukito, starts dating his childhood friend, Homan Yui, after she confesses her feelings. However, their story takes a turn when their mutual friend, Teshigawara Kotone, begins to seduce him using her body. Torn between the guilt of betraying Yui, who loves him wholeheartedly, and the physical allure of Kotone, Yukito finds himself at a crossroads: will he give in to a relationship with Kotone or remain faithful to his pure love for Yui?

"I'll make my wish come true, no matter what it takes. Even if it's abnormal, sinful, and utterly arrogant."

Eventually, Yukito starts to recognize the abnormal sexual desire within himself. What is its true nature?

The burning flames gradually transform into carnal lust.

[Translated from the official site]