[Exchange of bride + palace intrigue + sisterly comparison + scumbag boyfriend and girlfriend's ultimate fate]

My cousin and I got engaged at the same time.

She married the heir of the Duke's family, and I married the second son.

It's quite a story that cousins ​​married their own brothers.

Who would have thought that the crown prince would die on the battlefield, and the title of duke would fall to the second son.

To get rid of her reputation for bringing bad luck to her husband, my cousin turned to my fiancé.

On the eve of my wedding, my fiancé asked me to request to become his concubine.

Although it is a bit unfair to you to be a concubine, what more could an orphan like you ask for than being able to marry into the Duke's mansion?

Your cousin is the legitimate daughter of a marquis; are you perhaps trying to outdo her and become the principal wife?

Everyone assumed that I would either compromise or stand firm and refuse to marry.

As a result, I told everyone: I want to marry the deceased young master.

...