@alphazet god forbid i hurt the feelings of these fictional characters lol.
i also feel there's insidiousness to it because the whole marriage/bride thing is portrayed as very chast and "pure". I don't buy these 14 yo being this virginal and thinking about "oh,cute wife make me lunch, i blush" and nothing else.
I keep seeing this use of marriage in these sort of manga, at first glance it seems the author is trying to portray this "elevated" relationship where the characters aren't just "horny" for each other, but that they REALLY care and like each other BEYOND physical atraction, yet it almost always comes off as insincere, forced and insidious, like they are trying to avoid the "carnal" side of love. You can love and cherish and have a deep emotional bond with someone, doesn't make you wanna not desire them, or that you only have pure, cute thoughts about them. I keep seeing all these portrayals of sexual thoughts as something to avoid, to be ashamed of, to be cast away deep in the mind. And it's an all too common thing, too. Why not just say "i wanna be this girl/boy boyfriend/girlfriend?" because the sexual aspect of this kind of relationship is more upfront. A husband and wife have breakfast together, go shopping, pick up children from school. Sex is only a way to produce offspring (you always want kids when you are married after all, right?) in this scenario. It's more easy to portray a pure, chast, virginal idea of a relationship.
I'm not saying people shouldn't get married, or have kids, or that they can't have this ideals for their lives at a young age, just that i find that most of the time this way of portraying young love is actively avoiding more interesting and difficult topics and that they consciously or unconsciously are trying to push certain ideals (find love young, conform, marry and have children) that, even if not necesarily bad, are certainly just one side of the coin. Also that this portrayal seems to be the standard for these sort of cute, fluffy love comedies, with the complete opposite being the ecchi and harem sub-genre, where sexuality and sexual desire is usually played for laughs and again, the MCs are usually either these chast, virignal zen monks that can always avoid sexual desire, or these horny-ass dogs that can't keep their pants up and almost always get beat up as a result.
The more nuanced manga, where serious thought is put into both the virginal/ideal side of love and the more carnal aspect of it are few and far in between and that's really sad.