Feels like a One-Shot, but on the other hand also feels like, that once the daughter and the husband really moved on with their live she will lose her memories of her former life. I don't believe the author will do something like the husband marrying her once she is of age, rather that each one from the family will have their own life.
@melonpan@Walter_vi_Britannia Like I said in a previous comment that part was a bad phrasing on my part when translating it, he meant that he started making his own lunch when he was in school (stating that he had some experience at cooking) but now has been almost 20 years since the last time he cooked (It doesn’t mean he stopped right after school, he might have kept cooking from time to time but at some point he became too busy with work and stopped completely, as showed in one panel where his wife was the one making his bentos).