Sayyiduna Abu Musa al-Ash'ari (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said concerning the man who takes an oath of ila' from his wife: if that man wishes, he may take her back within the four months; and if he firmly resolves upon divorce, then the same waiting period ('iddah) will be binding on the woman as is binding on a divorced woman.
Tabarani recorded it. Its chain contains a narrator, Yusuf bin Khalid al-Samti, and he is da'if (weak).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الطلاق / 7834