[Society issues. That made things even tougher, she was sure.]
Is there anyone else from home that would really be upset about it? You're in a different place here. I wouldn't think you'd have to worry about what others think. Especially if they don't like really know what things are like back home for these situations. You have a really great opportunity here if the two of you can work through your differences about the other stuff.
I would definitely stay away from the "I told you so" type stuff about that other relationship. Just be there to comfort them and let them know that you're still willing to be with them despite what happened. The other person might feel a little foolish, kind of a thing like they now know you were right, and maybe they feel like diminished because they didn't listen to you in the first place. If there was some way you could let them know that it's okay they made their choice, and you'll be there now to help them cope if they need it. Everyone makes bad choices now and then, and part of recovering is having friends to help put things back together afterwards.