Nure Nezumi-tachi no Koi

Yoshi, a student in an all-boys high school find his only solace in Urakawa-sensei, the school's nurse. Urakawa is a fresh breath of air with his gentle demeanor and attractive appearance. But there's more than meets the eye as sensei seems to be close to another student named Sugao. Yoshi is in for a big shock as he learns things he wished he never did.

Official English 2: https://toomics.com/en/webtoon/episode/toon/5386