Sayyiduna Sha'bi (may Allah have mercy on him) said: "If a missing woman's wife becomes pregnant by her new husband and the first husband returns alive, she will be separated from the current husband, then she will observe the waiting period ('iddah) for the first husband, and she will have a share in the inheritance."
Hadith Referenceسنن سعید بن منصور / كتاب الطلاق / 2939
Hadith Takhrij«أخرجه سعيد بن منصور فى «سننه» ترقيم الدرالسلفية برقم:، 1761، 1762، وعبد الرزاق فى «مصنفه» برقم: 12341، وابن أبى شيبة فى «مصنفه» برقم: 16977»