Does the waiting period (iddah) begin from the date of the new divorce certificate instead of the date of the initial pronouncement of the Khul' judgment, and is it permissible for the divorced husband to enter the apartment of his ex-wife, who is the custodian, and claim that the divorce is invalid and express his desire to spend the night there after the Khul' judgment, knowing that the apartment contract is in his name?

The waiting period (iddah (definition)) begins when the husband pronounces the divorce or when the judge issues a divorce decree. The husband is not permitted to enter upon his divorced wife, and the religious guidelines must be observed, such as avoiding privacy (khalwa (definition)) and ensuring proper covering (satr). It is not permissible for them to sleep in the same place unless the apartment is spacious and each occupies their own separate facilities, such that neither is exposed to the other's private parts ('awrat).