Tamaranaitesho?

Synopsis

"You can have the professor, but... share half with me." Itsuki, an art student, discovered that the professor he admired was having a sexual relationship with another student. Feeling betrayed, Itsuki's crush began to turn into a dark lust!　Which one of the two will the professor choose, the obedient or the scheming? (Source: Ameiro, translated)