Anon.
Your are in my thoughts.

Best to keep the Horse in front of the cart for the moment and not jump too far ahead.
A step at a time.
Glad you called the Crisis Centre. Keep calling them if you feel yourself getting too frantic. Support is essential and while we here can only offer you a place to air your feelings, Women's Centre will offer face to face help and good non-judgemental advice.
I would , myself, call the Police. They may be able to help locate them and that would help a lot in putting your mind at rest regarding the safety of your Son and the stability of your Spouse at this time.

Where did they just return from? Is there a chance that Spouse returned there?

Put you first for the time being and talk to anyone that will listen.

May all resolve itself to the higher good of all concerned.
PM if you feel the need to.
Love and Light (at the end of this tunnel)
Jude