I don't know, I don't really want to complaint, but...
Okay, the new girl is annoying, I admit that. But the way Hori doesn't really reject her (in romantic perception) will of course only make him jealous. And then she just wants them not to fight but doesn't help anything, just plainly stupid, in my opinion. Just imagine that the boyfriend is the one who does that, I bet Hori will just punch him violently because of her jealousy.