Sayyiduna Ali (may Allah be pleased with him) ruled, concerning a woman who married during her 'iddah, that the two of them are to be separated, and she is entitled to the dowry because of what was made lawful of her private parts; and she is to complete her 'iddah, then observe the other 'iddah as well.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العدد / 15540