Replica: Revenge of the Ex-Wife

Aoi grew up constantly being made fun of and bullied for her appearance. After going through one bad experience after the other in school, she finally gets to marry the man of her dreams who loves her for who she is. However, he too eventually seeks out someone better-looking and cheats on her, resulting in their divorce. Oddly enough though... the woman he cheated on Aoi with is the same girl who bullied her throughout their school years...! Now Aoi's on a mission to get revenge on the man who cheated on her who is now married to the woman who made her life miserable. She has her face reshaped, her name changed to Sumire, and slowly begins to find her way into their lives... (Source: MangaPlaza)