Anime romances typically involve 15-year-old virgins. That is not just idealistic; it also simplifies the story a great deal. The boy doesn’t have to worry about catching venereal disease from the girl’s previous partners, for example.
Wotakoi breaks the mold by introducing a female character who is not a virgin as the romantic heroine. It is not clear how much sex people have in this show; Japanese fictional characters are considerably harder to figure out than real live Japanese people.
For the most part, this show relies on the gawkish, innocent tropes of romance between virgins, but these people are not virgins. They just seem to have acquired some sexual experience without acquiring much emotional maturity.
It’s fashionable to say that the friendzone is not a thing, or that the friendzone is just a bad rephrasing of “unrequited love,” but that’s not exactly true, and this show explains the complications. The heroine treats the hero as a reliable friend first and foremost, regardless of whether they are sleeping together. The heroine doesn’t have any trace of that dewy-eyed feminine vulnerability that makes a sexual relationship truly romantic – not with the hero, anyway.
So rather than saying that the “friendzone” exists only in the imagination of jilted boys, I would say that a one-sided lack of sexual chemistry is typically what makes the “friendzone” a reality. However, back in the days before easy divorce, there were lots of marriages with barely-functional sex lives that managed to produce children even though neither the husband nor the wife was very satisfied with the sex.
As far as I can tell, Japan currently has a problem with sexless marriages. There are apparently quite a few middle-aged married couples who have given up on sex. I get the impression that the hero and heroine could get trapped in a sexless marriage quite easily.
The characters are a little bit likeable and a little bit unlikeable. They are very much flawed people.