Yuuki is a regular salaryman descended from mages, and to strengthen their spiritual power, he's been engaged to someone from a Chinese family with strong spiritual power all his life. When they finally meet, his partner Shunen turns out to be a young man with loose morals, and Yuuki is not interested, until he finds out that as a "floral pearl," Shunen needs to have sex or he'll die (or something like that). Thus begins their adventures as an engaged couple. Interesting and funny, but it's not finished and unlikely to be updated any time soon. Trigger warnings: dubcon, drug (roofie), attempted rape.
Unmei no Hana