Help me please

Don't know when was the last time I felt this alone and distressed.  My ES has been the center of my life during his entire 37 years on earth.  We went through his father passing when he was only 10 which drew us so close.  (my mother and dad - his grandparents died the same year.)   That left the 2 of us totally alone in the world.  Thankfully at my job there were a group of Christians that surrounded me and put me on my pathway with God.  Two years later I married a wonderful man and the 3 of us had such a good family.  About 7 years ago he got involved with a gal who has no use for anyone except her family.  At that time, he was the divorced custodial parent of 3 children - we were so very involved in helping raise the children.. They had a child together 6 years ago and another one 4 years ago.  He had become very distant.  Now he has cut off all communication without any warning or reason.  My phone is blocked, "unfriended" on face book.  The last message I received told me to shut up and he never wanted to talk to me again nor would I ever see the kids again.  My DH is trying so hard to help me but my heart is so broken.  Can anyone please tell me what to do, what I can do, how do I get through this?  I know you all have more experience than I do and I would like to hear from some of you.  Feeling terrible and so alone.