Older uke younger seme

A manga about an older uke who is either a teacher or a nurse at a school, and the seme is a student, the story was heart warming about their love for each other. I remember that the story started with the seme at school and in the final chapter he was in his 30s. And the uke was in his late 20s early 30s and at the end he was in his 50s i think.There was no drama, just love..