The Host with a Little Boy and His Gentlemanly Neighbor(2019)

Komochi Host no Shinshi na Rinjin

Seiya is a nightclub host who is raising his late sister's little boy Tenma with Ibuki's (his neighbor/lover & an author) help. Seiya's days are filled with love and happiness, and he hopes they'll go on forever. But, his problem is that he cant make himself go all the way with Ibuki. Is it natural for lovers to have sex? But, it looks like he'd be the bottom!! Seiya's feeling panicked when Haruto, a popular and handsome actor, declares his love for Ibuki!!

(Source: Renta!)

Note: Includes one extra chapter.