The female lead becomes (reincarnated?) as the villainess from a novel she read. The original villainess married a guy that she loved, but he didn't love her. She even bore a son for him but the guy is still indifferent to her and so she kills herself in front of her son (original male lead) and traumatises him. The female lead said in the story that the original female lead helps the son heal from his trauma.
Lilienne Islar died an abusive mother, a neglected wife, and a cast-off stepsister. So when she suddenly opens her eyes again as her younger self, she decides to set things right with the people in her life. Luckily, her stepbrother’s a secret softie who’s easy to win over. Her fiancé, on the other hand, is a magic-powered war machine doomed for insanity. With an illness draining her mana daily, will Lilienne have the strength to save her future husband and maybe even the whole empire?
The main character is the villainess character in a novel she once read; her purpose in the story is to give trauma to the male lead. As mentioned in the synopsis, she abused her child and was neglected by her husband. And this includes killing herself in front of her (sleeping) child.