Mother-In-Law, I Won The Game

Here’s a three-line summary of my past and present lives:
Past life: A cheating, indecisive husband, a vicious mother-in-law, and a brother-in-law who called himself a “man of ripe charm.”
Present life: The opposite of that husband, the opposite of that mother-in-law, and the opposite of that brother-in-law.
Satisfied.
*
“You’re really lucky, huh? What kind of mother-in-law in this world lives nearby and does all the daughter-in-law’s work like a servant?”
After enduring mistreatment from my in-laws and a cruel marriage, I died the day I found out my husband was cheating.
But when I woke up, I was in a regret-based romance novel—as the villainess and the fiancée of the regretful male lead?
If I stay like this, I’ll end up just like before—mistreated by my in-laws and husband until I get kicked out.
But I had absolutely no intention of repeating my past life.
This time, I plan to live a wealthy, peaceful life on my estate—no husband, no in-laws, just me and my handsome commoner lover, along with the inheritance from my parents!
Step one: peacefully break off the engagement with the male lead.
I was just trying my best not to offend my prospective in-laws, the most powerful family in the empire, when—“Mother.”
“Did you just call me ‘Mother’?”
“Ah, no, that was… I misspoke—”
“You misspoke? No, you said it just right.”
“…?”
“Well done. It sounds lovely. From now on, call me ‘Mother.’”
…Why do you like me this much?
“Dain…?”
And now my awful mother-in-law, brother-in-law, and cheating ex-husband from my past life…?
Why are you all here?