After Time Travel, I Fell in Love with the Prime Minister's Daughter

This is a sadomasochistic novel. The male protagonist is lovelorn in real life. For some unknown reason, he time travels to the book and accidentally becomes the bodyguard of the prime minister's daughter. However, he is amazed that the prime minister's daughter is too similar to his ex-girlfriend. During this period, he experienced a series of stories such as a major case investigation and the emperor's marriage. The loyal prime minister's family was actually judged as treason. The young lady was living in danger and was humiliated. I rode a horse to rescue her, but an even more incredible truth was involved.