Analysis of When you loved me

There are two births; the one when light
   First strikes the new awoken sense;
The other when two souls unite,
   And we must count our life from thence:
When you loved me and I loved you
Then both of us were born anew.

Love then to us new souls did give
   And in those souls did plant new powers;
Since when another life we live,
   The breath we breathe is his, not ours:
Love makes those young whom age doth chill,
And whom he finds young keeps young still.