Answer:
I have joy in bringing two together, but darning my existence! My life hangs by a thread, filled with ups, downs and resistance!
What has 4 fingers and a thumb, but is not living?
I have a pet, his body is full of coins
What goes up let's of a load and come back down
You do this into someone's ear when you want to be discreet.
Sometimes I am white, sometimes I am dark. Most people love me. What am I?