Legal Question in Immigration Law in California

Technically, your husband, because of his TN status, remains a resident of Canada--regardless of the length of time he works in the U.S. The TN is a temporary, non-immmigrant visa that implies, ultimately an unabandoned residency in Canada. While a California court might profess jurisdiction because of his physical residency in the U.S., it could be dicey. There is no way that he could force you to stay in the U.S. because you are a dependent, non-immigrant. Upon your return to Canada, you could file for a divorce after meeting your province's residency requirements. I think a family law judge in either country would award physical custody to whichever parent reacquired Canadian residency. Your child has dual citizenship in both countries.