Chamin's Favorite

I once read a manga, that really catched my interest but as you can guess, I forgot it's name and didn't save it ;-;

I only remember the sidestory: A guy (friends with the main character) is in a relationshio with the schoolnurse who's male and the 'teacher' left the scholl because he didn't wanted both of them to get in trouble. Meanwhile there was a guy, who was bullying the friend of the main character because he was in love with him :D

please help, means a lot :3