Act Governing Relations between the People of the Taiwan Area and the Mainland Area Article 53

Where one spouse is any of the people of the Taiwan Area and the other spouse is any of the people of the Mainland Area, the legal effects of their marriage or divorce shall be subject to the laws of the Taiwan Area.
中文原文 臺灣地區與大陸地區人民關係條例第53條
夫妻之一方為臺灣地區人民,一方為大陸地區人民者,其結婚或離婚之效力,依臺灣地區之法律。

English translation for reference only; the Chinese text prevails. Not legal advice.