The first thing you need to do is contact a lawyer. Maybe your case falls under sex trafficking. The US Govt is very tough on that. Your husband can be forced to give you compensation and also face jail time himself. Second, if he has abused you mentally or physically which I think happened, you can get a waiver for removal of conditions, in case you want to keep your GC. Either way, you have to be strong to get justice for yourself and your son. Tell him that if he doesn't take you back with him, you will report to the authorities in your country and/or US Embassy that he has abandoned you. Just don't let him go scot free!
The problem is, you can't tell that directly to someone you know. Before anything happens, we will become the bad guys so I am trying to be supportive. I have a strong feeling about that guys bad intentions but keeping it to myself.