Contract Marrying Because I Am Terminally Ill

"Please be my husband for just one year! I only have one year left to live." The way she chose to escape from her vicious family was marriage. "You have a secret lover, right? I'm going to die anyway. I'll be your air-like wife to fill that empty space." It was nice to escape the house by proposing to Duke Kaiyen, the Grand Duke of the North and a war hero known for being cruel... "Gwama disease is not an incurable disease. It shouldn't be." The duke is so kind to me that it's melting my heart! Duke, I thought you have a lover...? (Source: Kakao Entertainment Corp., translated)