What is the ruling on a wife refusing to sleep in her husband's bed due to smoking, and what is your advice to her to avoid discord and divorce?

Smoking is forbidden (haram), and the wife must repent and quit it. The wife is obligated to obey her husband in the marital bed, and she is not exempt from this due to his committing sins. However, if the smell of smoke is very harmful to the wife, she does not incur sin by abstaining, and the husband must remove the harm from his wife.