Unhealthy relationships are not usually considered a very popular novel theme. Usually, a healthy relationship meant that two people were equal in terms of emotions, psychology, morality, and so on. They also had the foundation of mutual respect, trust, and understanding. However, in some novels, the relationship between two people might become unhealthy for some reasons, such as distrust, mutual harm, or because of some reasons, they could not be together. These plots might make the readers feel heartbroken because they might feel the pain and loss between the characters. Some of the possible heart-wrenching scenarios included: - The characters realized that their relationship was not as good as they had imagined and began to feel depressed and disappointed. - For some reason, the characters can't be together with each other or are forced to separate, which may cause damage to their feelings. - Misunderstandings, quarrels, or conflicts between characters that cannot be resolved for some reason may cause damage to their feelings. - The characters experience certain setbacks or difficulties such as losing their jobs, falling ill, family problems, etc., which may cause damage to their emotions. These plots may make the reader feel the pain and loss between the characters and may make the reader want to know more about the relationship in order to better understand the feelings between the characters.