Your life with your girls sounds wonderful.  It is heartwarming when
your children want to be with you, and are with you all the time....  it is
so fleeting.  As to waking at night for the little ones....  I used to wake
at the shift in breathing pattern...  nothing, nothing,  so rewarding and
fulfilling as comforting a child back to sleep. It is what good nature
meant....  And so sad to hear a child cry and be left a alone when they are
so dependent.
     Where does the adult energy come from?  The same place the love for the
second child comes from.  "I love you with all my heart", I would say to my
wife and then first born and then second born....
Best,
Leland