[✓]My Fiancé is in Love with My Little Sister

[SPOILER]Illya's multiple lives explanation

Illya, the FL, who doesn’t see herself as the protagonist of her own life, has been living through countless time loops, throughout which she never gains any kind of happiness or peace. It always begins at that tea party, the tea party where her fiance, Soleil, meets her beautiful, fragile, and (according to Illya) the heroine of their world younger sister, Sylvia. Throughout all the time loops, not all things remained the same, a previous foe became her best friend in one life and at one time Soleil made the bare minimum effort in their relationship and Illya in every life tried different things to end up away from her fiance and family because no matter what the unchanging constant in all timelines was Soleil tender love for her younger sister.

Her first and original life
Illya got engaged and fell in love with Soleil at the age of 5. Due to the vast class difference (Soleil being of a much higher class), Illya despite working extremely hard is riddled with anxiety and an inferiority complex of not being worthy enough for Soleil so she plays the stereotypical "villainess" chastising any lady who she felt threatened by. But when she realizes that the fiance who looked at her with eyes devoid of any warmth, looked at her younger sister with such a loving gaze, she gets enraged due to jealousy and yells out at Sylvia about using her sickness to take everybody’s love from her. Soleil gets angry at her and complains to her parents. After being treated like a disappointment, Illya puts up with everything quietly.She still gets married to Soleil because she is his wife material but he neglects her and often leaves her alone and spends time with Sylvia at her maternal home. Everybody knows about this but nobody stops him. One day news arrive that Sylvia was attacked by bandits and died. Soleil loses his mind over Sylvia’s death and in anger accuses Illya of her murder. Upon hearing the news of Sylvia’s death, Illya unconsciously smiles slightly in relief. She fixes her expression when she realizes what she did but Soleil already noticed the slight change in her expression and is convinced she did it. Illya is thrown in prison and abandoned by her family. Despite there being no proof, Soleil keeps searching for it and I guess fabricates some while Illya keeps faith that he will save her.Soleil’s friend meets her and cries and tells her to stop waiting for him but her faith stays on and Illya dies in prison alone, waiting for Soleil.

Her second life
Illya wakes up back at that first meeting tea party. She realizes what has happened and controls her anger and sense of betrayal so that she doesn’t get into trouble again. She tries her best in this life and hopes she can do better since she knows the future but events keep changing to bring Soleil and Sylvia closer. She just lets it happen because she didn’t want Soleil to get mad at her because she knew it wouldn’t make a difference. It would just make him hate her more. She once again marries Soleil. She uses her smarts to move up in society but she comes off as cold and calculating. She sends out guards to catch the bandits who killed Sylvia in her last life and realizes the bandits being there was a coincidence and not a premeditated plan.So somebody must have used the chance to pin the blame on her to get rid of her. She saves Sylvia and hopes their future will now change for the better. But soon, news comes that Sylvia is in a critical condition. Soleil panics and rushes to meet her and Illya says she wants to go to but he stops her. When she tries to follow after him, the butler blocks her way, just like their last life. It dons on her that the letter was sent to Soleil and not her, even though it is her sister who is ill and that it didn’t seem like it was the first time this happened. She realizes her parents would never commit such a breach of etiquette which meant it was Sylvia exchanging such personal letters with him. She tries to leave but faints. When she awakens, the doctor tells her she is pregnant. The news that was supposed to be the start of their new,happy future came at the worst possible time. She refuses to tell Soleil when the doctor tells her to inform him so he can accompany her because she knew when she insisted on going to meet Sylvia with him, he looked at her like he doesn’t want her to interrupt their time together. She later tells him and he smiles at the news but doesn’t look the least bit happy. He informs her Sylvia’s condition has worsened and she wants to meet her. Illya goes and neither her mother nor Sylvia notices her belly or congratulates her about her pregnancy. Sylvia selfishly cries and asks Illya for forgiveness saying she is in love with Soleil and that she doesn’t want to die alone. Illya doesn’t say anything and leaves. Soleil rages at Illya asking what she said to Sylvia that made her cry.Illya says she said nothing but Soleil doesn’t believe and says because she is so cold-hearted she must have done/said something. He then goes on to accuse her of infidelity and doubts the father of the baby. Illya faints and the doctor then tells her that she pregnancy could be dangerous to her health. Illya refuses and plans to go through with the birth to prove the baby is Soleil’s. Soleil never visits Illya. Illya finds some comfort in the support of her childhood knight, Al. Al has seen all she has been through and jokes about running away together. She refuses. She kept him as her support while trying to maintain a certain distance from him because the last life he was also accused of Sylvia’s murder to fill in any holes in the accusation against her. She finally gives birth to a son but dies before even seeing and holding him.She dies alone, while Soleil is away comforting Sylvia, and even without Al who at some point was reassigned.