Custody and Visitation Issues: Custody Arrangements Overseas/Dual Citizenship

My question involves a child custody case from the State of: California.

I have had plans to obtain dual citizenship for myself to England for quite some time. I plan to work out there, own property and now I have even met someone who I love very much out there.

But the dilemma I have now is if I'm allowed to pursue my dreams with my son from my previous marriage. Me and this person want to make a life together but I also do not want to force him to leave his country, job and family/friends. Even without this person I still wanted to own property in England and wanted my son to attend a highly educated British school.

What would happen if I did marry this guy in England. Would my son ever be allowed to spend 50% custody living in England? I know my ex husband would say no to this but is this something that would be out of my ex husbands hands that he would have to live with? I want to give my son the best life and my ex is more concerned on what he wants and would not move countries even if it means helping out his son more.

So just wondering if I married this guy in England/owned property in England if my son could spend 50% custody there with me even with me ex husband saying no?

Custody and Visitation Issues: Custody Arrangements Overseas/Dual Citizenship