@Delilah
Spoiler!
This creates a conflict, eventually bursting the abscess, because it's a point on which Jae-Young doesn't want to give in. He prefers to write like that, that's it. Mistakes are okay, it's his identity, and Sang Woo just has to make an effort. He leaves the house but tells him by text that he loves him attaching all the words.
They end up explaining themselves, Jae Young's planned a whole treasure hunt in the house for Sang Woo to understand him better.
Sang Woo agrees to go back on the rules, in particular that of having s** only on weekends, because hey, Jae Young's still irresistible. xD