Good luck to you both, but a loan is a loan, so try to pay it of before he leaves, even if it means you borrowing the cash here to send over there.
Like many have said if you are planning to be together for ever, you must know all there is about each other, debts and all.
Call it what you want but i am sure there are many that has been asked for this and that and i am sure there are a few still paying , as long as you are happy hat all that matters.