Mr. D souza,
I have read your autobiography. Child should have been with you if she has left the country permanantly and kept child in the care of her parents instead of giving it biological father ( when you are still in india). but may be because she was financially insecure she might have thought of returning back in a year or so after making some good money to secure childs life.
Even if he was under grandparents care even for temperory period you should have availed your visitation rights to be connected with the child.
What has happened in the past you cannot change. you have control on present and future. Now that you have remarried and settled in kuwait. you will have your childrens someday or may be u already have.
yes it is very painful for a father to remain detached with the son but now it will be more difficult to be connected with the son when you have ur present family. you will have to balance both the relations.
your son must be 12 years+ and will be mature enough to understand the situation. he will some day come to know about your feeling towards him. or else you write to him a mail. the best what you can do is to give him all the financial help for education and atleast meet him and talk to him when you are india.
hatred/sympathy/pity for wife will be useless. think about what you can give rather than thinking what you cud have done or given. you will remain a father to the son even if you are remarried.