Though no explicit reason is given why the exiles wanted to marry foreign women, we can make some guesses. The prophet Malachi mentions that some Jews sinfully divorced their Jewish wives in order to marry foreign wives (Malachi 2:11. Malachi 2:14). The Jewish wives are mentioned as the wife of your youth,
suggesting that these men were older and thus now looking for a new younger wife.
Other reasons for the marriages might be a desire to strengthen economic ties with local pagans in order to promote business opportunities.
2 And Shecaniah the son of Jehiel, of the sons of Elam, addressed Ezra: “We have broken faith with our God and have married foreign women from the peoples of the land, but even now there is hope for Israel in spite of this.