Hmm. Even if you ignore or dismiss the age gap for a blink, the romance here still feels a bit empty; We see that Mamoru and Nariyuki like each other, and even I must admit that the chemistry is there, but there's not a lot of reason WHY. The attraction between them feels like lust and lust alone. Part of it is because we don't know enough about both parties, because the story doesn't spend too long in fleshing out the characters' internal life, but part of it is also because we spent too much on the (rather meh) banter; almost every chapter it's justMamoru pouting and blushing at Nariyuki's teasing and like--yeah? sure? What else is there?

Now add the age gap, and it does get a little bit oop and oof and eugh. The relationship doesn't feel like something that will last. The gap between their personalities feel too vast to cross.

But at least Hiro the child is so cute.