This is a popular sadomasochistic novel world called "Love in the World". All characters live according to the plot set by the author - the female protagonist endures all kinds of torture, the male protagonist pursues his wife in the crematorium, the second female lead is responsible for causing mischief, and the second male protagonist silently guards.
Until one day, all the characters suddenly awaken to self-awareness. They find that their lives are controlled by an invisible "author" and that all pain and sweetness are scripts. What's even more frightening is that each character has a "Character Value Panel" in his mind - [Sadness Value] [Sweetness Value] [Tool Man Index] - these values determine their fate.
What the protagonists don't know is that the book they are in is actually an "experimental site for sadomasochism literature" in a higher-dimensional world. The purpose of the experiment was to test "whether the oppressed character will repeat the oppressor's logic after awakening" - and the observers of the experiment were the authors who wrote "Sadism Love".