One of the most common complaint of this manga is that they hated that the focus shifted from the first couple, and then it repeated change focus of couple for every volume, which is hilarious, that they're dense enought to not understand it's simply how the mangaka decided to format his story. Those readers should pick up endless repetitive trash like Amano Megumi to see what happened when the story have to focus on mindless ecchi with no progress at all in the story for 100+ chapters. Which is what will happened if there is only one couple in the manga