You ever have a friend, someone that you got along really great with? Supported every way you could, treated with love and respect, really felt comfortable sharing things with?
Then, for what appears to be no reason at all, that friend just stops talking to you? Stops acknowledging your existence? Then you just find yourself in extreme pain because someone you care about so much, someone you love more than just about anyone, does the one thing you never thought possible?
You try every single way you can think of to rationalize it. But ultimately, all you are is at a loss, just in a constant state of stunned. It gets to the point where you sometimes just wish they would tell you to drop dead and get lost because even as excruciatingly painful as that would be, at least there would be communication.
The missing is the hardest part.