Comment by Woojo on Jinx - Chapter 70.5

@Woojo because that is the only way Jaekyung knows how to connect with him. He's a dumb@ss, so he doesn't realize that he's in love with Dan and he wants Dan to care for him the way he used to, but Dan is hurt. He is guarding his heart because Jaekyung trampled on it before. His actions towards Jaekyung are cold and indifferent; Jaekyung doesn't like that. He wants things to be like they were before, so he settles for s3x because that's all he can get.