When my boyfriend went abroad on a job assignment, we knew it would be difficult for us to maintain our relationship because distance is not a joke. There was no internet yet, no cellphone either, and overseas call was very expensive. The cheapest communication was postal mail. We were writing each other at least 2 times a week. To avoid confusion, our letters were numbered since it takes 2 weeks for the turnaround. So I am sending letter #10 while reading letter #7 from him. Those letter exchanges helped a lot because we were able to surmount the odds. And when he came back home, we were just like before with our relationship.

So my advice is the constant communication and, of course, understanding.