Conjoined Twin

Dear Conjoined Twin,
We used to be exactly the same,
No one could tell the differences between us two,
People would have great difficulty naming the two heads on our shoulders,
But as to be expected things changed,
But I never expected it would be this horrible,
I never expected that the once kind mind would become so deformed,
I never thought you would enjoy hurting others for fun,
And I never thought I would enjoy hurting myself,
Dear Conjoined Twin,
You're one half of me,
We share the same body,
Even though we can be two different people,
But soon that has to change,
You can't go back,
And I'm so sorry my dear conjoined twin,
But there's only one escape method,
And even if that happens,
What will happen to me?
Will I disappear as well?
Maybe you can't have one without the other.