Adult PC Game: Wife Stealing- Female Teacher Training Logbook v1.00 by Black Lilith Archive

Among the students and the staff, Shirou has built a reputation as a benevolent teacher. However, he has a dark side... Behind the scenes, he has secretly gained control over the school by making Principal Kanako submit to his huge cock. And now, his next target is a young PE teacher called Makoto. After sending her husband - a cafeteria worker - on a business trip, he used sleeping pills to incapacitate Makoto and take her away to a hidden room somewhere on the school grounds. There, he revealed his true nature and, with his stout cock, began chipping away at her chastity...!

This VN is a prequel to a hentai anime of the same name, which does not have a VN of its own.

Wife Stealing- Female Teacher Training Logbook v1.00 by Black Lilith Gameplay Preview