An Avreich once came to Rav Ovadiah Yosef and complained that he can't convince his wife to stop wearing a sheitel. Rav Ovadiah ruled very forcefully that a woman must cover her hair with a tichel or hat and that sheitels are no good [he explains his reasoning in the fifth volume of Yabia Omer. Note - My Rebbe's Shlita's wife wears a sheitel, my wife wears a sheitel, Rav Moshe Feinstein's wife wore a sheitel - and many, many more. If you are married and reading this then in all likelihood you do too. This is not a post against sheitels:-)].
Rav Ovadiah surprisingly told the Avreich that he must divorce his wife. This was quite shocking and he was very hesitant to follow the Rav's words. He asked around and was told that just recently a similar case had been brought to Rav Ovadiah and he advised NOT to get divorced. [Note: According to halacha, when one's wife goes in an immodest fashion then he must divorce her. Ask a rabbi for contemporary applications of this halacha וד"ל.] The Avreich couldn't understand why he was being told to make such a radical move.
He returned some time later and was again told to divorce her. He had little children and was caught in a dilemma - the word of the Rav vs. his own strong desire to remain married - sheitel or no sheitel. His dilemma was solved some time later when he discovered that his wife had a non-Jewish boyfriend on the side [which is indeed grounds for divorce by any measure].
He then understood the ruach ha-kodesh of the Rav....