What is the ruling on masturbation practiced by the wife after intercourse, what is its appropriate punishment, is a second marriage a solution to this, what is the cure for this habit, and what is her retribution if she repeats it?

Masturbation is a forbidden habit that leads to harms, and its practice by a married woman is even more reprehensible. If the wife repents, she should not be held accountable for something she has repented from. It is not permissible for the husband to ask her if she has returned to practicing it, nor is it permissible for her to inform him of that. If the husband learns of her return to this sin, he should advise her kindly and remind her of Allah. There is no specific legal punishment for this in this world or the hereafter. Marrying another woman is permissible for one who is able to support her and deal justly between his two wives, and it should be resorted to for a benefit or need, not to punish the wife.