Since My Time is Limited, I'm Entering A Contract Marriage

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 tgought you have a lover…?