I'm very glad you wrote, and very sorry to hear of your predicament. Yes, here we would say that you have "Battered Wife Syndrome" and are thinking like an abused person. Your statement "My husband before marriage had promised me that I would be allowed to work." is a clue that you began the marriage by giving up your power as a career woman. If you have to have permission to work, you are already compromised. I know you are very smart, or you would not have your degree and your career history.
Although I normally strongly support intact marriages and families, in this case I think it's good that you left. Your husband's family apparently saw you only as a source of money and as a servant. You have to walk the line between being an independent person and being acceptable in your culture. However, if you were working as a dentist, you do have some freedoms as a single woman. I don't think there is much to love in your husband, although I'm sure he was charming when he was trying to lure you in. But he doesn't value you or your child except as possessions, so it's probably wise to stay away from him. No, I don't think this marriage is good for you or your son. Stay with your own family, get back to your career, and proceed with the divorce. Document all the abuse that you suffered, with dates and names of those who abused you, for the court.
I understand why you can't get counseling, but you do need support. Do you know a wise and kind elder person who could help guide you? If so, ask that person for guidance and support.
Stop longing for marriage -- instead, focus on creating a good, solid foundation for your son. When you are stronger, and free again, you can look for another partner, who is a more balanced, kind and caring person who will be good to you and your son. You want to be partners with someone, not a servant. "The Courage to Hope" "Coping with Critics" "What is a Dysfunctional Relationship" and "Setting Boundaries and Saying No" will help you reorganize your life and stand up to your in-laws. It Ends With You: Grow Up and Out of Dysfunction will help you redefine family and mental health. Take good care of yourself and your son, and your future will be bright.
For low-cost counseling, find me at LoveForever.com