There are different answers to this question. 1) In terms of law, 2) In terms of the Bible, and 3) In terms of diverse cultures. Let’s talk about the law on Earth first. There is no specific law which states that you cannot marry a person outside of your own race nor is it considered wrong or immoral. After all, love cannot be defined by who you marry in the end.
The Bible does not also specifically state that it is wrong to marry someone outside of your own race, although in the Old Testament, Israelites were prohibited from marrying certain groups but it was not based upon their ethnic, cultural or national differences. In terms of cultures, some cultures prohibit marrying into a different culture, but we cannot blame them. It has been part of their tradition after all.