I Faked a Pregnancy, but My Husband Returned

Before the original story begins, I reincarnated as a lowly noble burdened with debt. I managed to survive by selling bits of information to an underground guild, but even that has its limits.
However, as the story is about to start, I know that the villain’s family is looking for a fake contract daughter-in-law to pretend to be pregnant to delay the death declaration of their missing eldest son. If I take on that role for just a few months, I could earn a lot of money.
I was planning to live quietly as a dutiful fake daughter-in-law…
“If you stay here, I’ll give you all of Ekian’s inheritance.”
But the Duke, my father-in-law, likes me too much.
“Why solve everything with money? How about adopting her and remarrying her?”
The Duchess, my mother-in-law, wants to mess up the family registry.
“You did marry my brother, right? You won’t leave if he comes back, right?”
Even my brother-in-law, the villain of the original story, clings to me!
Meanwhile…
“They said after a while, they’ll divorce me and find me a good remarriage prospect personally.”
“…Remarriage? You mean to marry again?”
The head of the information guild, whom I used to sell information to, is acting strangely.
“That husband… he might come back.”
What nonsense is this? According to the original story, the eldest son of the villain’s family remains missing.
***
“E-Ekian? Is that you, Ekian?”
“You… you are back? Really?”
Impossible.
The eldest son of this house is never supposed to return!
“Yes.”
Who is this handsome man confidently walking into the mansion?
“I heard I got married. Where’s my wife?”
What? I suddenly have a super handsome husband!