How does the human heart break?

It doesn't.

It gets wounded

Scratched

Scarred

Scared

Sad

But it does not break.

It might be teared

Ripped

Dragged

Dumped

Stepped on

Smashed

Squeezed

Tighten

Harden

But it does not break

For it is the strongest 

Spiral pumping

Cornucopia muscle

In the entire universe!

It really just needs to be fed

For though it might not break

If one does not love enough

It will eventually stop.