Aijin Tensei: Sare Tsuma wa Shinda Nochi ni Fukushu Suru

Having lost her mother at a young age, Chisato grew up with her father. She married her university classmate Mayama Yuta, who is now the heir to a large company, and was meant to lead a happy married life, but instead finds herself treated like a “housekeeper” by both Yuta and her parents-in-law.
Then, one day, she witnesses her husband walking affectionately with a young woman, Mitsui Runa. When finding out he betrayed her, she explodes with anger at Yuta, but a struggle with Yuta leads to her getting hit by a car. When Chisato awakens in the hospital, she discovers she’s actually been reincarnated as Runa, and thus, she vows to dedicate her new life to getting revenge on Yuta.
(Source: Drama-Otaku)
~~ Adapted from the manga series "Aijin Tensei - Sare Tsuma wa Shinda Nochi ni Fukushuu suru-" (愛人転生 ―サレ妻は死んだ後に復讐する―) by Ikeda Seiko (池田聖子)