Is it a big taboo to have an interracial relationship nowadays?
The world is becoming more homogeny and with it, we see that dating someone with a different background is not a big taboo anymore, however even if culture has changed about interracial dating, and people are more accepting nowadays, the couple will still feel the impact of a long history of a no-no dating from different race, racism and even different expectation.
An important Bible verse about understanding interracial marriage is 2 Corinthians : "Do not be unequally yoked with unbelievers." That last word, "unbelievers" is of key importance.
A Christian should not marry a non-Christian no matter how kind and good they are. Deuteronomy 7:1-6 tells the Israelites to destroy all the inhabitants of the Canaan land and not to intermarry with them because they would "turn your sons away from following Me, that they may serve other gods." The same key concern of 2 Corinthians is again expressed here.
The harlot, Rahab, also of another nation, is included in the lineage of Christ as recorded in Matthew 1.