It would seem to me that so long as you have trust, then there is little to concern yourself over.

JM is right, though. Talk to your bf, let him know what your concerns are and at the same time, reinforce to him the fact that you do feel there is trust between the 2 of you, and despite the distance, you have faith in what you share.
Trust is the key and communication is essential to maintain a distant relationship.

To date, I've been in a long distance relationship for 3 years now, (he resides in Holland), and I can personally contest that it is not easy. We have over-exceeded what the emotional bond can provide, and have been seriously struggling by trying to create a fill to the void from what the lack of physical creates.

I wish you all the best.

Shangrala