The Eldest Princess Went Crazy After Being Forced to Be a Concubine

I rescued the prince in distress, and in return, he escorted me to the capital. And when I said goodbye to find my relative, he tried every possible means to persuade me to stay. I thought he was trying to help me find my long-lost relatives. But I only found out when the Crown Prince's wife ruined my innocence and forced me to be the Crown Prince's concubine. It turns out that the Crown Prince's wife is infertile, and I am just the fertility tool that the Crown Prince found for his wife. They, as husband and wife, thought that I was just an orphan and couldn't get out of their hands. But they don't know that I am the eldest princess living among the people.