Taking the oath of Zhihar thrice

Q: I am a Muslim young man, Al-hamdu lillah (All praise is due to Allah). I am married and have five children. My wife is the reason behind our problem and I was unaware of the Islamic ruling. I said to my wife, "You are unlawful fo me like my mother". A year later, I said this to her for the second time. I repeated it for the third time another year later. Please advise, did she become unlawful for me or not? Is there a Kaffarah (expiation) for this saying?

(Part No. 20; Page No. 323) A: Your saying to your wife, ''you are unlawful for me as my mother'' is explicit Zhihar (a man likening his wife to an unmarriageable relative). You have to offer Kaffarah for Zhihar. This expiation is to set free a believing bondsman, and if you cannot, then you must fast two successive months. If you are unable to fast, you have to feed sixty needy persons. You must not approach your wife before making the Kaffarah as you have pronounced Zhihar three times. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.