In "Romeo and Juliet", why does Romeo think that banishment is worse than death?

has just gotten married
to the woman/girl that he thinks that he is completely and totally in love with.  Immediately
following this he is in a street brawl with s cousin, , and kills him which leads to Romeos
banishment from Verona to Mantua.  In Act 3, scene 3, Romeo learns of his banishment from the
Friar.  Romeo says,      

     There is no world without Verona walls,

       But purgatory, torture, hell itself.

      Hence
banished is banish'd from the world,

      And world's exile is death. Then
€˜banishment

      Is death misterm'd. Calling death €˜banishment,

      Thou cut'st my head off with a golden axe

     
And smilest upon the stroke that murders me. (A. 3, s. 3, lines     18-24)

Here, Romeo reveals his feelings on his banishment.  To him, the banishment would be
worse than death because he would be taken from all that he knows and has known his entire life;
more importantly he would be taken away from his Juliet and would never be able to see her
again.  This would be worse than death because he is really alive, and being alive he will be
able to think about what he can no longer have.  Meanwhile, if he had been killed for his crime,
he would not be able to ponder over Juliet because he would be dead and his thoughts could not
drive him crazy as they could in his banishment.  Romeo reveals this when he says,

     'Tis torture, and not mercy. Heaven is here,

      Where
Juliet lives; and every cat and dog

      And little mouse, every unworthy
thing,

      Live here in heaven and may look on her;

      But Romeo may not €¦  (A. 3, s. 3, lines 30-34)