What is the ruling on the wife's daughter residing with the husband after puberty, and what are the limits of interaction between them; and what is the ruling on the husband's sons residing with the wife and her daughter?

One must distinguish between three types of social relationships within this new family:

1. The wife's relationship with the husband's sons: If the questioner contracts marriage with the wife, her sons become forbidden to her, and the relationship between her and his sons becomes one of mahramiyyah due to affinity. 2. The wife's daughter's relationship with the husband: If the questioner consummates marriage with his wife, her daughter becomes unanimously and perpetually forbidden to him, and she is the stepdaughter. The relationship between the husband and his wife's daughter becomes one of mahramiyyah due to affinity. 3. The wife's daughter's relationship with the husband's sons: This relationship is considered like that between a non-mahram man and woman. If they approach puberty and she reaches the age of desire, the rulings on prohibited intermingling between the sexes apply to them. This necessitates avoiding residence in one house with shared facilities to prevent falling into the evils of intermingling.