People only want the nice things on a relationship and not the responsabilities (They arent dating yet though) That's why they are always cheating or never settle down at all.
I myself find what Amano did, Adorable. She is acting just like a jealous wife who has longed to see his hubby all day just to find him fooling around with someone else, thankfully it was a misunderstanding. May be annoying but that's how you know people really like you.