Haven't read the whole thread yet, just the OP...
I live in Italy, married to an Italian, but I am English.
I knew that having a child together would potentially leave me stuck out here without an anchor or a support system here if we split up. Not cos I am dead clever, simply because I'm on husband 2.0 and the first was was Thai, with us living in BKK. So I had the advantage of a crash course in how things can turn out with kids in the mix, by watching my friends getting a huge shock when they realized they were trapped out there unless they were prepared to leave their children.
DS is 11 now, my marriage is fine, (most days, we have had our moments over the last 16 years), but I feel that if it went belly up the onus would be on me to stay here for the sake of my son having the sort of relationship he has right now with his father, and avoiding DS taking my place as the person who is unhappy "far from home".
That doesn't mean I am without sympathy, I really do know what the reality entails when you are not at all enjoying the place you have moved to AT ALL but feel trapped. But right now you need to think about things in terms of your son's needs before you concentrate on your own.
Remember that any action on your part that could be construed as attempting to take your son out the country without permission could come back and cause you terrible trouble. Do speak to a lawyer to find out your rights, do speak to your consulate to find out what additional support or advice (if any) they offer. then sit back and digest that information and see what you can work out with your husband as a compromise, because somebody is going to have to. If not all three of you on some level.
You have to bear in mind that as desperate as you are to take you son "home", your spouse is equally desperate to keep him "home". Even while being adversaries you are both coming from the same place essentially.
Your husband is trying to avoid the risk losing his child permemantly by allowing said child to leave the country with you because he does not trust you will come back.
If the tables were turned, would you not do the same ?