Any type of a distance is going to be disadvantageous to a relationship. Besides being apart from each other for prolonged periods of time, there is the chance that one or the other partner is going to end up finding somebody else, if even for short periods of time during their times apart. Even if it turns out to be a fling, or other short-yerm affair, there is a very strong chance that the relationship may end up totally ending. Even texting, skyping, and simply phoning is not going to be enough, if the separation of distance becomes prolonged. Too much time apart and the relationship starts looking like they are separated, Eventually, this can become the reality.
A long distance relationship takes the closeness and intimacy out of a relationship. Even though the two of you are still communicating, and invariably see each other from time to time, love can start to disintegrate over time. Differences can come to the surface more, if the long distance relationship becomes prolonged. Even if it doesn’t, problems can still form, as there is essentially temptation with the distance and time that goes with it. Many romantic partnerships endure, but can still be pressured and harmed. It can depend on each couple, their personality and mindset, with their situation and circumstances.
Many other events and circumstances can contribute to problems in a relationship. But trying to keep work and everything else going in your life, while facing the strains of being apart is very taxing. With so many romances crumbling and collapsing anyways, a distance relationship is just another pressure in a long series of current stresses and strains. In most cases, the partnership will survive. But if it becomes a necessity to remain separated-short-term separation can easily becomes long-term or even permanent. This reality is already a contributing factor to many break-ups. Even strong relationships need to be revived. A loss of personal contact, the intimacy and sex that goes with it is dangerous to its stability.
There is also the loss of grand personal moments, like both partners being there to see their child walk, or the other partner not even being present during the birth of their baby. The missing of grand moments can eventually contribute to relationship decline, and hidden resentments can easily come to the surface. The couple may already be distanced due to relationship problems. Even if they are not, it is important to try and see each other as much as possible.
Deployed soldiers constantly have this problem. But their spouses fully expect and understand this when they get married. For other couples, unless there is something really good coming out of these separations, and a lot of understanding, at the very least some damage will be done. In most cases, repairable. But something that both partners should watch closely.