Tatsuya Tanaka

About

He was 5 at the start of the story, and now he's a 20-year old with a baby face. A virgin with a girlfriend of the same age. Sensei was his crush. While he still has memories of that time, he's been considering cutting ties with her to prioritize his relationship with his current girlfriend. Unfortunately said girlfriend resembles a younger version of her, and as such he still loves her deep down.

(Source: the manga's character introduction)