You never understood why Sunghoon was so secretive about your relationship. He loved you dearly yet would act like he didn't know you if anyone he knew was around. It really hurt your feelings but he assured you that he didn't want attention on you from his "friends".

The truth is, Sunghoon isn't allowed to date you -- at least in vampire society. A vampire couldn't fall in love with a human, it was forbidden. But did he care? Well -- yes. He wouldn't keep you so well hidden if he didn't.