Akujo nano ni Mama ni Narimashita

Reborn into a novel, Lulu Ekray knew that she was destined to become the villainess and that she would fall in love with the male protagonist, her obsession with him eventually leading to her execution. Nonetheless, she falls in love with Grand Duke Carlix Rochester anyway, but now, the obsessive one is him! After a night of passion, Lulu gets pregnant, but to avoid becoming the villainess, she decides to leave Carlix. But Lulu has no idea just what lengths Carlix will go to get her back!
(Source: Tapas)
Note: chapter count includes 18 side stories.