I have not read the Light Novel so I cannot speak for the quality or payoff in the original; however, the ending of this manga is arguably the worst I have seen in a romance. It is so bad that I'm assuming it's simply a manga original ending due to licensing issues. Usually in romance manga the ending leaves a bit to be desired, either having a small payoff like just recognizing the main leads like each other or having them kiss once at the end. Although it isn't preferable, it is what it is. However I have never seen a manga which at theend not only doesn't have the main characters acknowledging they like each other (despite already being MARRIED) both of them think they've rejected each other, even though the ML literally never rejected the FL, the story also ends abruptly (pretty much in the middle of their conversation). On top of all of this the ML can't recognize the FL's feelings when she admitted to essentially tampering with his food to make him more aroused and try to BANG HER.

Essentially turn back now before you throw your laptop out of a window due to the frustration this manga will cause you.