spoiler!!! I am so incredibly glad this had a good ending. damn I'm relieved. I know tha...

I was quite sure it's the opposite. Of course, I would like a happy ending for Shion, but could you please elaborate?

Based on parts of the novel i read before, I believe that Nezumi wanted Shion by his side simply because he seamed so pure and harmless, and since Nezumi distrusts everyone nothing short of perfectly harmless is safe enough for him. Once Shion showed that he isn't that pure, Nezumi had no more reason to stay close to him, because even he is dangerous. Other possibility is that he felt he made Shion unstable and thus he should leave him for his sake. Which is true, Shion basically has a yandere swich.

And believe me, I really wanted to come to a different conclusion, I really love the story, I watched the anime at least ten times and cried and raged at the ending each and every time ╥﹏╥

I definitely see your point...Reading your conclusion does make it seem really sad...
You're right, it's not a happy ending. However, I usually read much sadder stuff. For example, Banana Fish (which made me ugly cry and gave me depression for 3 months) or The Promised Neverland (which also made me cry). Basically...the fact neither of them died made me so happy... and it gave me so much relief that I just accepted it as a happy ending. I just delude myself into thinking Nezumi eventually came back and now they live together in the new city ╥﹏╥

I haven't yet finished either of the two stories you mentioned, and I'm yet to see if they'll make me cry (⌒▽⌒) Funnily enough, I don't really cry to truly tragic stuff, often I just think of tragic endings as neet, I mean, you can hardly get a more conclusive ending then one where someone, or everyone, dies.

Here what saddens me is the idea of Shion cluelessly and unconditionally loving someone whose feelings were always shallow and passing while not getting it in the slightest. In his mind, it's just like love of his life decided to leave him without any reason and he keeps on waiting in confusion, while Nezumi will just keep being himself somewhere in the world.

I guess life stuff just makes me more sad then death stuff. If Nezumi had died at least he would have a valid reason for not being there, and Shion would be able to live on eventually. And if Shion had died, well, he himself wouldn't really mind it, and while there are people who would grief, he would be remembered as a hero and however sad they get there would always be gratefulness and happiness in their grief, which would make the ending pretty.

I'm not saying I would prefere them dead, but... I would like this to have been a love story, that's all. Although the sucky ending is probably the part of a reason why I love it so much.