What is the Shariah ruling on a couple returning to each other after three divorces, given that one of the divorces occurred after intercourse when the wife was not pure, and another divorce occurred when the wife was in the last days of her menstruation? And is the difference of opinion among scholars considered a mercy?

A lawful divorce is one that occurs during a period of purity (ṭuhr) in which the woman has not been engaged in sexual intercourse. As for divorce during menstruation (ḥayḍ) or post-childbirth bleeding (nifās), or during a period of purity in which the husband has had intercourse with her, jurists have differed on this matter. The majority of them hold that such a divorce is valid, while others maintain that it is not valid because it is an innovative (bidʿī) and forbidden divorce, based on the Almighty’s saying: (O Prophet, when you [Muslims] divorce women, divorce them for [the commencement of] their waiting period). If someone you trust issues a fatwa (religious edict) stating that the third divorce is invalid because it occurred during a period of purity in which your husband had intercourse with you, then there is no harm in adopting this fatwa and returning to your husband, while being cautious of divorce pronouncements in the future.