Is the waiting period (iddah) calculated during the third menstruation, or after purification from it? And is the divorce nullified if there is passionate kissing and embracing between the spouses, without intercourse, during the third menstruation and before the waiting period ends?

The divorce pronounced by the husband is valid. The husband's kissing of his wife is not considered a رجعة (revocation of divorce) according to the majority of scholars. Rather, a رجعة occurs through a statement or an action. The husband has the right to take his wife back before the expiry of her iddah (waiting period). The iddah expires upon the completion of the third menstruation, according to the more preponderant opinion. The husband must treat his wife well and provide for her and their children. The wife has the right to claim back from her husband what she spent on herself and her children with the intention of claiming it back.