I would never let him go if i were you

If you let him go back to China you set up your marriage for failure. I could be more blunt even if you go back with him there are still a lot of temptations in Shenzhen.The short answer is stay in the states or Canada for the kids, for your family and for your marriage. Money is not more important than all of these so even if you could make more money in China I would choose not to go back.