I'd Rather Marry a Spirit Tablet Than Be a Concubine

My cousin and I were engaged at the same time. She was engaged to the heir to the duke's house, and I was engaged to the second son.
But the eldest son died in battle, and the second son has now become the heir. To escape her reputation as a husband-killer, my cousin turned to my fiancé.
On the eve of our wedding, my fiancé decided to take her as his first wife and me as his concubine.
Everyone thought I would either swallow my pride or defiantly refuse this union. Instead, I declared, "I will marry the deceased young master instead."
Become a concubine? No!
I'd rather marry a spirit tablet.