Sorenari Ni Shinken Nandesu

A Boys Love manga by Auso Kai. Title translates to "I'm Serious In My Own Way."

Oosawa had known Yoshioka for a long time... As his customer, Yoshioka came in and out of the shop with different boyfriends all the time. He thought he knew fully well what kind of man Yoshioka was. But when tragedy hit Chizu, his one and only daughter... and his capability as a single father was questioned... Yoshioka came out of nowhere and offered help. Slowly but sure, Oosawa learned that the man he despised was very different than what he appeared to be!