Nobody's supposed to be here

So I placed my heart under lock and key
To take some time, and take care of me
But I turn around and you're standing here

How did you get here?
Nobody's supposed to be here
I've tried that love thing for the last time
My heart says no, no!
Nobody's supposed to be here
But you came along and changed my mind

This time I swear I'm through
But if only you knew
How many times I've said those words
Then fall again, will I ever learn
Knowing these tears I cry
This lovely black butterfly
Must take a chance, and spread my wings
Love can make you do some crazy things