What is the ruling on turning off the lights during intercourse if the wife insists on it, and is she entitled to refuse and thus be sinful for it?

It is permissible for spouses to see each other's entire bodies, and the husband has the right to enjoy his wife in all ways permissible by Sharia. The wife is not entitled to prevent him from looking at her body during intercourse unless it causes her harm. Jurists have differed on whether a wife's prevention of her husband from looking at her face constitutes nushooz (disobedience). The husband should treat his wife kindly and strive to solidify their relationship based on mercy and understanding.