Beth R. v. Donna M., 2008 WL 615031, No. 350284/07 (a trial court decision from New York County):
Absent overriding legislation, recognition of out-of-state marriages is governed by common law doctrines and comity. New York courts have long held that out-of-state marriages, if valid where entered will be respected in New York even if under New York law the marriage would be void. "(I)t is a general rule of law that a contract entered into in another State or country, if valid according to the law of that place, is valid everywhere.... (T)he rule recognizes as valid a marriage considered valid in the place where celebrated." There are only two exceptions to this rule. New York will not recognize either a marriage prohibited by positive law of this state or a marriage abhorrent to New York public policy. The abhorrence exception is so narrow that it has been applied only to marriages involving polygamy or incest....
Courts have recognized other out-of-state marriages that are repugnant under New York law. Historically, New York law prohibited a respondent who was divorced on the grounds of adultery from remarrying during the former spouse's life. Yet the respondent's remarriage in another state was recognized as valid in New York if the other state did not preclude the remarriage of an adulterer. A valid out-of-state marriage that was voidable under New York law because a spouse was underage was recognized as valid in New York. Common law marriages, although not recognized in New York, will be upheld if validly entered into under the laws of another state. New York recognizes as valid out-of-state marriages by proxy, although such marriages cannot be performed within New York....
Accordingly, defendant's motion to dismiss this divorce action on the grounds that the parties' Canadian marriage is void under New York law is denied.
UPDATE: Thanks to commenter Klerk for a pointer to the decision, and also for a pointer to a similar decision last month in Martinez v. County of Monroe -- an appellate decision in that case, not just a trial court decision, and one involving a right to spousal health care benefits based on a Canadian same-sex marriage.