I would actually find it quite disturbing if Jaeha had already likes Eunho when he was young because of the 8 years age difference. The thought of for example a 16 year old being in love with a 8 year old just doesn't sit right with me.... So i think it's understandable that Jaeha still tries to deny Eunho's feelings, because in his head he still sees Eunho as this young boy that he used to know and he needs to overcome that first.
Might have been so but I don' t find the age gap disturbing though. I'm a sucker for age gap except shotacon. I think Eunho has a hard time coming into terms of his sexuality to made matter worst he finds himself having feelings for his childhood friend who he treated as his younger brother or vice versa. Well, let's see how the story unfolds, can' wait for the next chapter.
Putting a distance is best to keep Eunho from hurting and for Jaeha to realize his true feelings. I keep getting this thought though that Jaeha have long realized his feeling for Eunho when they were young, you know the whole childhood friend cliche in yaoi.