I thought that this was a really sweet fic. You've nailed most of the characterization, making Ron realise things at just the right moment (that he would, I mean. Not too slow, not right off. Just right - er, I mean; Ron!), and having Hermione hesitant to explain.
My favourite line has to be, "Wonders why it feels as though he just lost a Quidditch game or a chess match, and a million times worse." That's just such a great line, a way that Ron would relate things to and it's really powerful for the reader too - plus it made me smile despite the sadness!
One thing that I wasn't sure on was Ron's sudden change of emotions. We know he has quite a hot temper, so I was a little surprised to see him going straight from being angry at Hermione to pleading with her.
I thought all your description was brilliant, it really puts the reader in the scene, with the description of Hermione walking away and when we first realise Hermione was crying, at the beginning.
I absolutely loved the ending! How could anyone not?! It was just perfect! The whole thing was wonderfully written, and I'd definitely advise you to write some more! Great job.