恋してダディ [Koishite Daddy]

男手ひとつで幼稚園児の凛太郎を育てるサラリーマンの佐藤は、ひょんなことから隣人の大学生でゲイの高橋と親しくなる。子供好きでなにかと手助けしてくれる高橋に惹かれ始める佐藤だが、離婚して間もないのに不謹慎だと自重する。しかし、高橋の家に行きたいとだだをこねる凛太郎に苛立ち、思わず叱りつけてしまい…！？
キュートでスウィートなファミリーライフ♪

From Mangaupdates :
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!