Being away from the one you love is hard, it takes a lot of courage to be away from the one you love because of certain reasons. One of the main reasons why this happens is because of financial status.
But absence indeed makes the heart grow fonder because it makes you miss that person, it gives the lesson of giving importance to a certain person and it somehow let each of you learn the value of presence.
Most partners, lovers or anyone who is in a relationship specially if they had been into that relationship for a long time would tend to not give much importance anymore when their partners are around but being away for a period of time makes the other party or both parties miss their presence. Thus testing the love that they had indeed promised.