I think the blonde guy didn't really like him that way, but got so weird around him because of his secret (making the black haired guy the mc of his manga)? Or he got scared after what he said on the beach thinking "no homo" and ran away. He seems to not really believe that the black haired guy may have liked him back then.
The "secret" they are talking about are probably the true feelings of them both, that the black haired guy liked him and the blonde guy used him for his manga. I think both secrets will be uncovered as soon as that manga will be published...
Yeah it seems that at the end he was going to go buy it
There are parts in the history that are changed by the mangaka almost all of the first half of the history is not real( look how the mangaka is dressed) but then it becomes memories ( the mangaka is using gakuran) the only real time they hold hands was at beach but only just the fingers because they stopped because the friends came ( all the others times were just the history of the mangaka) and the other guy didn't hold his hand un front of his friends ( you can ser un the picture they are not holding hands)
The secrets were that they were both un love but didn' t confess because the world is not so kind
But maybe they can be together if he reads the history
Sorry * you can see in the picture
They don't end up together!? WTH!? They clearly likes each other but decides to leave each other because what? I don't understand the last one with the pictures sent to him.