My Marriage Contract With the Lord Marquis

The marquis, an older man almost twice Ingrid's age, introduces her to love and imprints intense pleasure on her pure body. Forced into an unwanted marriage due to the debts her brother incurred, Ingrid escapes from her predicament by entering into a contract marriage with the wealthy Marquis Tristan, who only wants an heir. Her honeymoon with Tristan is filled with impeccable affection day and night, and every time he passionately and sweetly pursues her in bed, Ingrid is intoxicated with the pleasure. But this relationship will only last until the birth of a child. She knows this, but she can't find a way to suppress her young love... Source: MangaPlaza