We review a district court's legal conclusion de novo, seeking to determine whether the court correctly interpreted the law. In re Strong, 2000 MT 178, ¶ 11, 300 Mont. 331, 8 P.3d 763 (citation omitted). A finding of federal preemption will be sustained in the area of domestic relations only where "Congress has positively required by direct enactment that state law be preempted." Strong, ¶ 11 (citation and internal quotation marks omitted).