In the Talmud, interfaith marriage is completely prohibited, although the definition of interfaith is not so simply expressed.The Biblical position on exogamous marriage is somewhat ambiguous; that is, except in relation to intermarriage with a Canaanite, which the majority of the Israelite patriarchs are depicted as criticising.That decree was probably even more damaging to them than the original decree of expulsion from Spain because it indicated that this time the Inquisition-Church-Christian society was far more serious than anything previous.Within the first 50 years after the expulsion, there was a steady exodus of Marranos from the Iberian Peninsula.
Forced divorce and excommunication of foreign women previously married to the Jews of Israel does ocur in Ezra chapter 10.
The forced conversion of a quarter-million Jews in Spain was, in spiritual terms, a Holocaust never equaled in the long exile of the Jewish people.
Even under the worst of circumstances of assimilation it never matched the finality of conversion. These were Jews who had officially converted to Christianity but saw themselves as Jews and practiced Judaism in secret as much as they could.
In several places in the Jewish Bible, there are relations which appear to be intermarriages - for example, King David is described as marrying the daughter of the king of Geshur, (PLease note - this is not what Nehemaih cited refers to.
refers to not buying grain on the Sabbath and forgiving debts in the 7th year.