The ruling on one who swears by the forbidden that he will not marry, then marries

Question:
The listener (M. H. M.) from Yemen, residing in the city of Khobar, sent a message containing several questions, stating: About sixteen years ago I got married, and after a year, Allah blessed us with a son. A discussion arose between me and my wife regarding the child, and out of my joy for him, I said to her to please her: "Women are forbidden to me after you," meaning that I would not marry again. After one year, she passed away, and I remained unmarried for seven years. After that, I married her sister, and now I have three children from her. Do I bear any sin for what I previously uttered? Are women forbidden to me after her? Do I have to pay an expiation, or what? Please inform us, may Allah reward you.

Answer:
It is not permissible for a Muslim to forbid what Allah has made lawful, whether it be women, food, clothing, or anything else; for Allah the Exalted says to His Prophet (peace and blessings be upon him): [Surah al-Tahrim: 1]. Therefore, it is not for you or anyone else to forbid what Allah (Glorified and Exalted is He) has made lawful . You must pay the expiation for the oath you made, which is feeding ten poor people, or clothing them, or freeing a slave. This is what is obligatory for you. Since you have married, praise be to Allah, you must pay this expiation: feeding ten poor people, where each poor person receives half a sa' (a dry measure of about 3 kg) of dates or other staple food of the country, such as rice or wheat. The amount is approximately one and a half kilograms by weight. You give this to ten poor people, each receiving half a sa', meaning approximately one and a half kilograms, for each of the ten poor people, of wheat, barley, dates, or rice, as expiation for what you said: "Women are forbidden to me after you." This is the expiation, along with repentance and seeking forgiveness for what came from you. And success is from Allah.