Father who might have to move home, outside USA

Hi, I am looking for advise on what my legal rights are if I leave a marriage?  I am not in a high paying job so if I leave the marital home I believe my only way of paying for my living expenses and child support / alimony is to move home to my own country to work (back to my parents), which is outside of the USA.  My wife excludes me from as much of my sons life as she can and any time I question anything I'm told to mind my own business.  To make life easier for my son I try not to push the issue too much as it upsets him too much to see us arguing.  But the situation has become unbearable and the only reason I've stayed for as long as I have is because of him.  My son is 5 years old. 

The questions I have are:

1) What rights will I have regarding access if I leave?

2) Will those rights change if I leave the country?

3) Can I get a court order or make it a legal requirement that I can take my son home to my home country to meet his and my family?. My wife is current