Manga by author Kitazawa Kyou - Status ongoing

A high school teacher, Ueda Wataru, was rejected by a person he loved back when he was a high school student and has been timid in love ever since. However, he's now fallen in love with his student's father, Ippongi Kazushi, a Yakuza. Although Ueda knows that he shouldn't be, he's fascinated with the good looking Ippongi's sweet words...

From Shinmakoku Scanlations :Satou is a salaryman who is raising Rintarou, a toddler, by himself. After an event, he gets closer to his neighbour, Takahashi, a gay university student. Satou begins to get attracted to Takahashi who is fond of children and helps Satou a lot, but he held himself back thinking it would be too imprudent for him since he only got divorced just recently. Yet Rintarou starts throwing tantrums wanting to go to Takahashi's house all the time, and Satou is confused... What is going to happen? Here's a cute and sweet family story!