A parting always holds a measure of sadness, regardless of the circumstances (happy circumstances in this case). It is wonderful that both your son and his fiancée have jobs in these recessionary times, and opportunities ahead of them. I suppose it is something that he has not had to go abroad to work, and is in the same country. I am sure you will visit him, and he will visit you. With time it is even possible that as things improve he will again find work closer to home. Life does seem to be a kaleidoscope of partings and meetings, doesn't it?
All the best