Dont leave with my heart

I pulled myself away and no one saw at first
I faked that smile everyday even at my worst
tears covered by my make-up,scars covered up by shirts
and old habits flared up again, like a mad dog gone blood thirst
I did all i could to make myself feel great
and kept it all a secret as i watched what i ate
more secrets kept inside so the world couldn't see
that things had gotten bad again and i was losing more of me
I thought id lose this time for sure and wouldn't make it through
but something happened that i cant explain, on the day that i met you
a smile crept across my face and refuses to go away
i don't know whats got me like this Ive never felt this way
I'm scared for my heart and the fragile state its in
but still i let my guard down and don't bother to defend
so i have a favor for you, the most important part
please promise me that when you leave you wont leave with my heart.