Hi,
If you both love each other, you won't easily be tempted to go out with anyone else. Before he goes off to his new school, you need to have a heart-to-heart talk and agree to be faithful to each other and that if one of you will fall in love with someone else, for both of you to be honest with each other. That both of you will try to maintain communication with one another.
You actually don't know what the future holds. If you're meant to be together, it will happen.
Good luck to you both.