What is the evidence supporting the view that the marriage remains until the Iddah ends if one spouse converts after consummation?

Primary text

The primary evidence is the report that Safwan ibn Umayyah and his wife, Umm Walid ibn al-Mughirah, had a difference of about a month between their conversions; she converted on the Conquest of Makkah, while he remained a disbeliever until after the battles of Hunayn and Ta'if, yet the Prophet (PBUH) did not separate them, and their marriage was established on that contract. This narration's fame outweighs its chain of transmission according to Ibn Abd al-Barr. Another supporting narration states that 'Ikrimah's wife invited him to Islam after she converted, and when he converted, they both remained upon their marriage. Furthermore, figures such as Abu Sufyan, Hakim ibn Hizam, Abu Sufyan ibn al-Harith, and Abdullah ibn Abi Umayyah all converted before their wives, yet there is no known instance where the Prophet (PBUH) separated anyone based on this difference.