Partly it’s just a trap that manga like this fall into. All of the drama and tension is built around the conflict between desire and restraint, so if they give in and do the deed, the story’s effectively over. But the longer it goes without some resolution, the more irritating it gets.

I think part of the thing with this one in particular though is that it’s TsuyaTsuya, so the fact that they haven’t done it is one of the only things that distinguishes it from his countless hentais.