It is narrated from Ibn Shihab that Safwan bin Umayyah (may Allah be pleased with him) fled at the time of the conquest of Makkah, then came to the Messenger of Allah ﷺ and participated in the battles of Hunayn and Ta’if while still in a state of disbelief, whereas his wife had already embraced Islam. The Prophet ﷺ kept them both upon their (previous) marriage. Ibn Shihab said: There was approximately a one-month gap between the Islam of Safwan and his wife.
Hadith Referenceمسند الإمام الشافعي / كتاب النكاح / 1196
Hadith Takhrijاسناده ضعيف لإرساله اخرجه البيهقي في المعرفة السنن والآثار (4198) - ومالك في الموطأ، النكاح، باب نكاح المشرك اذا اسلمت زوجته قبله۔