You'd better take him to a gambling treatment center. Your insurance company can pay for this special treatment. Then you may take him to church, where he will make some good friends and have spiritual pursuit.
I believe that he will come back to you and your kid with your help and support. Your hu*****and is addicted to gambling because he feels frustrated, empty,and lonely. You should not desert but help him for your kid. No one is easy to survive in the USA. Hopefully, you and your hu*****and can solve your problem and live in peace again.
I used to be a volunteer in a gambling treatment center. I can be a witness to those who were addicted to gambling. Most of them can live a normal life after treatment. Trust your hu*****and and go ahead, and you will feel better. Never give up working hard and loving your family. I am sure that your family will live a better life after this special experience.