The Brainwashing Of The Impending Disaster Isn’t Being Undone

As the loyal hunting dog of the king, Oscar of the Serpentine ducal family is well-versed in dark sorcery. The second son of the Serpentine family, he confronts a looming disaster trapped in the most secret part of the mansion.
“If you release me now… I’ll spare your life at least.”
Zachary Thaddeus.
The moment Oscar met his blue eyes,
he realized he had been reincarnated into a bleak fantasy novel.
Zachary, a prince of the Holy Empire, was kidnapped by the Serpentine family and mentally broken,
becoming the protagonist who later tears the Serpentine family and the kingdom to shreds.
To survive, Oscar must break the brainwashing on this impending disaster.
After desperately undoing the brainwashing on Zachary,
Oscar chooses to marry to escape from the Serpentine family himself…
only for Zachary to return and burn down their honeymoon home.
“Fuck, you say you released me? You abandoned me.”
…?
“Was it so horrible just having me by your side? I asked you to let me stay close to you!”
…???
What should I do? It looks like his curse isn’t completely broken yet.