[@mdk] Apparently GRRM planned this all out from the beginning, meaning that he's been sitting on it for [i]twenty-five years[/i].

[quote=@Taaj]
So really, he knew his whole life how it would end.
[/quote]

I'm not sure he did, or at least not convinced that he was capable of understanding that knowledge or  acting on it in any significant way. We'll probably know for sure when it's revealed in the books (in however many months or years that takes).