Challenga's Manga

After repeated betrayals, the lady stops her attitude of trying to please her family members. She won't be a pushover nor will she let them use her like they have. That includes the "sister" that they all adored in her place

Reincarnated as a minor villainess, but now she maintains the family frugality and aims to protect her baby sister from becoming a first wife that suffers and dies while trying to give birth. Her enthusiastic determination to keep the ML from proposing and in his place peaks his interest in her. Now that they are married and she is being projected into high society, how will others perceive them and what might happen when the expect FL of the novel enters the sphere of their relationship and influence?

While the summary goes past the current situation, it does hold promise. She's a woman that reincarnated after being betrayed multiple times. First her people were, then she was personally by a man she loved. She was an empress and now she married a duke that is cursed and presently a large wolf. She is also managing his estate and revealing corrupt nobles