Is the wife sinful for taking her children from her first husband to live in another apartment and for visiting them despite her second husband's objection? And will his curses against her befall her?

If a man marries a woman who has young children, and he was aware of their existence at the time of the marriage contract and did not stipulate that they should not live with him, then he does not have the right to prevent them from living with their mother in his house. This is because his silence is considered an acceptance of that, and he is compelled to house them if they have no other guardian.

However, if the husband mistreats them and they are harmed by remaining with him, then there is no blame upon the mother for renting a special dwelling for them and going to them to attend to their needs, even if that requires staying with them half the week if they are in need of that, and the husband does not have the right to prevent her from doing so.

As for the hadith, "If a woman spends the night deserting her husband’s bed, the angels curse her till she returns," it applies when the wife abstains from her husband’s bed without a valid Shar’i excuse.