She was absolutely terrible and a downright villain to her 2nd husband in the previous life. Negligent, emotionally, and physically abusive. She just sat around, wasted resources, and didn't know how to cope with anything. I wanted to punch her. After her rebirth, she gets flashbacks of how poorly she treated the people in her life and feels immense guilt and disgust at her own actions. She gets her sh*t together and becomes serious to avoid her past mistakes. Instead of being a waste of space, she becomes a top rank scholar and solves issues of the Empire. She treats the 2nd husband significantly better and promises that she will completely devote herself to him. She takes care of him and protects him from the scheming of others. She isn't too over the top with her revenge schemes (feeding 1st husband food he can't tolerate so he gets the runs), like in other novels where it is complete overkill.
The main lead Chechun is freaking adorable (and sometimes annoyingly dense). He's been in love with the main character for years due to encountering her in their early teens. She saved his butt from getting kidnapped accidentally. He was spoiled, sheltered, and chubby, making everyone think he was a waste of space, including himself. He has an epic cute bonding moment with the main character as they share their insecurities with each other and he falls in love with her. He promises that he'll become the type of guy she likes, slender, smart, and graceful. He's really dense and fails to pick up on cues, but he is adept at finance and business. His devotion to the main character borderlines worship, but he's one of the very few people who has seen her good side and believes in her.