G.,
As a nurse, I have to tell you some of these mom's are correct. Pay close attention as to when he sucks his thumb. This is very important and see if there is something that you can give him or do for him when he does this, LIKE put your arms around HIM...... It is a very emotional thing. He has no control in his life right now and one thing is for sure, his thumb will always be attached, unlike his parents.... I know that sounds terrible, but see it through the eyes of a child. Your parents are there to let you know that your ok and when things are not going well with them or there is emotional upset within the home of any kind, children feel it, literally....When I was married to my older children's Dad, it was a marriage full of turmoil and my oldest daughter started sucking her two middle fingers and she did this usually when she was tired or in trouble for something...it was comforting and soothing to her, YES SHE HAD to WEAR BRACES.... That was ok for me, because her emotional well being was so much more important to me...If your son sucks his thumb when he starts school, then the other kids may make fun of him and that will fix the issue at least while he is at school. I would not Recommend any of the physical remedies that anyone is suggesting here. I would recommend that your ex-husband and you talk about possibly letting your children attend some therapy, possibly play therapy, its a very good way to find out what is bothering your child and how you can help him deal with it. I put both my children in therapy after my divorce, because it had a dramatic affect on them, even though I knew the seperation would be better for them in the long run, initally it was important that they found a healthy way to deal with their emotions and play therapy with a good child psychologist allows that... I know you have your hands full, but ultimately if you help him deal with his emotions in a constructive way, then you will be teaching him that his feelings matter and its important for him to feel SECURE. Ultimately, that is what all human beings need SECURITY...Financially, Physically, and Emotionally....
GOOD LUCK GINA
J.