Until You Unlock the Door

Overview

With that cold look, he feels this urge growing in his stomach... Makoto Tsuge and Kyouya Shirane have been friends since their sophomore year in high school. Makoto's friendly and gets along with everyone, but Kyouya's more of a loner who does what he wants and often picks on other people. Despite their polar differences, they've managed to stay friends into their adult years. However, the truth is they've each been working very hard to stay close to one another... This is the love story between a plain, friendly businessman and a fancy-free, gorgeous beast. Their ten-year relationship will turn into a loving one, and the key to that is their second kiss. (Source: Renta!)

Source: AniList