What is the ruling on a wife and another wife sleeping in the same bed with the husband, and what is the ruling on the two wives undressing and the husband embracing them in this situation, and is that considered zina (adultery/fornication)? And what is the ruling on the two wives touching each other in the same bed, and is that considered lesbianism (sihāq)?

A woman who is revocably divorced becomes a stranger to her husband once her waiting period (iddah (definition)) ends. It is not permissible for him to touch her, look at her, or be in seclusion with her. The husband's act of lying with this woman, or touching her, or kissing her, whether or not she is married to another man, is considered one of the gravest abominations and an act of immorality, amounting to a form of zina (unlawful sexual intercourse). If the husband incites her to seek divorce, he is committing the sin of instigating discord (takhbib). The cohabitation of two wives in one bed is permissible under three conditions: their consent, that the 'awrah (intimate parts) of one is not exposed to the other, and that he does not engage in sexual intercourse with one while the other is present. As for a woman touching another woman, it is forbidden if done with lust. It is the wife's right to reside in her own private dwelling.