Contract Marrying Because I Am Terminally Ill

I have just one year left to live.
I wanted to escape my wicked household, and the method I chose was marriage.

"You have a loving mistress, right? I'm going to die anyways. A wife who is like air that only fills the space, I'll become that."

It was great up until I proposed to the Grand Duke of the North, Duke Cayenne, a war hero rumored to be cruel, and left my home…

"Hyper-mana syndrome is not a terminal illness. I cannot let it be."

My heart is going to explode from Sir Duke treating me too nicely!
Sir Duke, didn't you say you had a loving mistress…?