Challenga's Manga

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?