Heart's addiction

Its a once-upon-a-time fairytale again.
This time, you were my choice of drug;
my latest addiction.
Started out fun
and turned into something I needed.
And overused,
Classic substance abuse.
Totally boring.
So, End of story.

But nothing really ends until the book is closed...
So far, the pages are still, and as wide as open.

Fill in the spaces; if you will.