Spoiler: Fl The FL is not the owner of the body. She read the events in a novel and then d...

Spoiler: Fl
The FL is not the owner of the body. She read the events in a novel and then died. At the same time, the old soul of the body died.When FL woke up ,her memory was almost lost. The important thing is that she is trying to remember and improve the relationship between father and son and fix the events of the novel that she read in her life before she entered the new body. She is partially amnesic, but she was noticing physical memory, such as the body’s reaction to a specific person, for example, her heart that was expanding with the Duke and the strange fear that she felt when she met her father.. What is important in the end is that she remembers the reason for her disagreement with the Duke and the reason for her rude treatment of her son,they live happily at the end and have a daughter.

Spoiler:FL's background
The reason for FL's bad relationship with her husband is that the FL is an illegitimate child,born from the count and the maid, but her father raised her with his wife,the countess as if she were their legitimate daughter instead of his daughter who died, and because of the wife’s hatred, when they were young(FL and ML), she sold the maid - the mother of FL to the duchy of of ML.

Spoiler: Background of ML's mother
ML's mother is of foreign origin and was one of the captives/not noble, and in order to become a duchess, she agreed with a witch that she would help her on the condition that she would steal her son Kian's(ML,the husband) happiness, which means she will not let him see happiness in his life.

Spoiler: Background of FL and ML
Because the Count’s wife sent the maid to the Duchess, and the Duchess(ML's mother), because of her feeling of inferiority because she was not originally from a noble family, was torturing the servants and killing them. During this time, ML and the FL got to know each other, and ML was helping her see her mother in secret so that her mother(the maid) would not get involved. She began to love ML and ML loved her, especially since FL discovered that the Duchess was tormenting and abusing ML as well, but one day the Duchess hits the mother maid and killed her, and from here their relationship was ruined, because ML became the son of FL's mother’s murderer.

Spoiler: How the marriage between ML and FL happened
After that, the Count was going to go bankrupt and marry his daughter to an old man in order to pay off the debt, ML decided to save her and marry her. However, FL who still saw him as her mother's murdered's son, was always hurting him with words and ignoring him. As for their son, she treated him like this as revenge for her past, just as the Countess treated her.

Spoiler: FL's father,other events,ending.
the Count would come to the palace every once in a while to ask for money, and he would criticize ML as being of low blood because of the origin of the late duchess,his mother,who was a slave/captive. The father would threaten the FL to reveal her origin to her husband. She hated him and was afraid of him. The important thing is that the FL gets her full memory back and tells the truth to ML and ML kills the Count and apologizes for the past,because ML was wronged like her, and ML apologizes because he was unable to protect her mother, but he was able to bury her in a safe place after she died and make her a shrine and a church. There is also part of the story about the witch of the forest - which was mentioned previously with the Duchess - and her bet with the FL, and many other things but i don't have the details.
In the end, Cassel,the son,loves Leah the OGnovel FL, and the FL becomes pregnant with a daughter and lives happily with her family.

(Ps. I (=・ω・=)didn't read the novel yet and this just from the novels review. Also this is not mine I just read it from somewhere)