One year is a pretty long time, and to have dated him for this long, a lot of effort was exercised to make it a successful realtionship. Why would you want to give it all away due to societalal defaults and sentiments?
I think I can relate to one or two reasons why you have doubts or difficulties picturing you two as married couples. You feel you might hurt or at worst, loose your family because they probably might not approve of the relationship. You fear that when you two get married and have children, your kids will be faced with the difficult choice of choosing which religion to follow or have faith in.
Pardon me for saying this, but I think you already have the answer. I want to take you for a mature and rational person, and in saying so, it's right to think that you careless what religious barriers you two have and that's why you dived into the relationship which so far has been great drawing from your own words. If it were left to you alone, you'd walk down the aisle. I think you should do so if it's what you want. You're doing it for your happiness and not your family's. At some point, we all leave our immediate families to start our very family. No one should go into such commitment without happiness as the rest of your life depends on the choices you make today.
And the possible thought on the kid's future with regards to faith, well, i guess you'll find a way out when it gets to that point.