Hi Kate,

Seemed like it could have a melody like that of,
"I'm Not Sayin" by Gordon Lightfoot

I had an idea pop up that I personally would do.
I hope you can appreciate that "I can't leave without my heart" is a good Country hook that I've given you.:

I’m not saying that it’s easy
I’m just telling you the truth
And I’m not sure that you’ll believe me
Even though I really need you to
Cause I’m not staying here forever
I’m not ready for that part
You know that someday I’ll be leaving
BUT I CAN'T LEAVE WITHOUT MY HEART

CHORUS
YES for now you have my heart
HOW MUCH LONGER I CAN'T SAY
BUT YOU STOLE IT FROM THE START

(or for a longer chorus three more lines and a Chorus rhyme scheme of ABACDC)

ETC., ETC.

Cheers,
Terry

P.S.
Went back and looked at Polly's contribution.
If you used my idea the song title might become "I can't Leave Without My Heart"
or "Without My Heart" in which case
Polly's section could become a nice bridge.