It may not make sense, but to me Badly Drawn Boy's "Silent Sigh" is the closest aural equivalent to a heartbreak.

Stop baby don't go stop here
Never stop living here
Till it eats the heart from your soul
Keeps down the sound of your
Silent sigh
Silent sigh, silent sigh silent sigh
Keeps down all move me down
Could we love each other

And the single most wrenching song ever written has to Eels' "It's a Motherfucker."

It's a motherfucker
Being here without you
Thinking 'bout the good times
Thinking 'bout the bad
And I won't ever be the same

It's a motherfucker
How much I understand
The feeling that you need someone
To take you by the hand
And you won't ever be the same
You won't ever be the same