
I don't want to find some excuse ti Shiki but maybe when he faced death after the bomb exploded he's started to think about life and future and change his mind. This is not a good reason, I know. This author used to let open ending to her mangas so we can imagine what we want and maybe that one day Shiki would tell the truth to Keigo...

He actually says he's going between guys. He keeps telling one he's too busy to be with him most days so that he can see the other one, and he tells the other one the first one is his boyfriend so that the other one won't get serious. I wouldn't have issues with him if all three of them had known what the circumstances were. One of the parts was in the dark, so yeah, it's bs.
Tbh, I really loved TJ's story but Nishikiori's was bs. I hated the fact that he was two timing, but I understand why. But I still hated it. It was horrible. In my opinion, really. I have a thing against two-timing shit and I just can't take it. And also the fact that he ends up with Keigo in the end is just fucked up. Like, does he even like him?????? What the fuck, man