The following question arises frequently nowadays: What should a married couple do if one spouse comes from a family that refrains from kitniyot and the other from a family that eats kitniyot? A similar matter was addressed by one of the great Rishonim, R. Shimon b. Tzemaḥ Duran (Tashbetz 3:179), who writes that they obviously cannot eat together at the same table while food permissible to one is forbidden to the other. Therefore, the wife must adopt her husband’s customs, for “a man’s wife is like his own body.” We learn that when a Yisraelit marries a kohen, she attains the status of a kohenet, and she may eat teruma. Conversely, a kohenet who marries a Yisrael becomes a Yisraelit, for whom teruma is forbidden. We likewise learn from the laws of kehuna that if the husband dies, and she has no child from him, she reverts to her family custom, but if she has a child from him, she keeps his custom. If she remarries, she adopts her husband’s practices. (When it comes to determining Jewishness, the mother is determinant; if she is Jewish, so is her child, regardless of the father’s status.)
- Moshe Feinstein (Igrot Moshe OḤ 1:158) adds that the wife’s status is similar to that of one who moves to a place where the accepted custom is different from his own. If he intends to settle there, he relinquishes his previous custom and accepts the custom of his new home (based on SA YD 214:2, OḤ 468:4, and MB 14 ad loc.). When a woman marries, it is as if she moves permanently into her husband’s house, and she must therefore adopt his customs. Accordingly, if an Ashkenazic woman marries a Sephardic man, she may eat kitniyot during Pesaḥ and need not perform hatarat nedarim (annulment of vows).
Igrot Moshe also asserts that she need not perform hatarat nedarim. MB 468:14 implies the same in stating that one who moves from one locale to another must behave according to the custom of the new place. It is implied that since this is the halakha, there is no need for hatarat nedarim. This is also the opinion of Kaf Ha-ḥayim 468:43. Additionally, in extenuating circumstances even Ashkenazic communities did not accept the custom of refraining from kitniyot and can therefore be lenient in situations of famine or sickness (MB 453:7). Similarly, two different customs in one household would certainly cause tension. However, Sidur Pesaḥ Ke-hilkhato 16:13 states that she must perform hatarat nedarim, and Ḥazon Ovadia (p. 56 and n. 10) states that it is better to perform hatarat nedarim. Nevertheless, in practice, she need not perform hatarat nedarim, and this is the common practice.
May Ashkenazim perform hatarat nedarim and eat kitniyot? Mahari Ben Lev §38 states one who refrained from eating kitniyot because he thought they are ḥametz may perform hatarat nedarim, but one who knew, or whose ancestors knew, that kitniyot is merely a stringent custom may not perform hatarat nedarim. Accordingly, Ashkenazim may not perform hatarat nedarim and eat kitniyot. According to Pri Ḥadash §468, one need not perform hatarat nedarim to annul a custom that originated in a mistake, and if they knew that it is just a stringent custom, it is possible to perform hatarat nedarim. (However, we need to examine whether he would apply this reasoning to a custom accepted by an entire community; perhaps even according to Pri Ḥadash hatarat nedarim would not be effective in such a case.) Ḥatam Sofer OḤ §122 upholds the opinion of Mahari Ben Lev. This is in fact the customary practice: we do not find Ashkenazim performing hatarat nedarim to eat kitniyot.