Have you considered cultural and religious issues?
Yes you heard me right, religion and culture. we like to tell ourselves that wont be a problem but religion and culture often become a problem when both of you feel strongly about your faith and heritage. I once watched a match making show where a man and woman were hitched by the match maker, everything was perfect between them except the fact that both refused to back down when it came to their faith and that relationship didn't make it beyond the first date.
Even if you think religion wont be an issue after marriage, it is still wise to talk about it before going in. Also if you are of different cultures you have to bear in mind that you may not always do things the same way since both of you have different backgrounds. Communication and trust should be extra important in your relationship, be sure to build a good and trusting relationship where both of you are free to express yourselves appropriately before the vow. Don't ever imagine you can convince him/her to adopt your faith and way of life when you get in or worse still believe it doesn't matter.
That being said, the good news is that a lot of people have married people of other cultures and religion and it has worked wonderfully well.
Do you think it is important to discuss your faith before marriage?