Depending on the personalities and approaches of both parties, maintaining a long-distance relationship can be time-consuming with little in the way of return on the investment.
The frequent e-mails, phone calls and cards sent through the mail take up a lot of time and effort, and as it turns out, keeping up with each other's news isn't necessarily the same as growing closer.
As more time passes, the distant object of your affections can begin to seem like something abstract and less than real. An e-mail in your inbox isn't the same as having someone nearby who can help you in person, who can share your day with you, and who can create new memories with you. The distance can be a serious wound to a relationship, and the efforts to maintain long-distance contact can seem like mere bandages placed on a gushing artery.
Eventually, the growing loneliness may make the wound too severe to warrant more "treatment" -- it may be time to declare time of death.
If concrete plans to reunite aren't in the near future, the projected gains may be too little to warrant moving the relationship down the temporal road.
Next: Is your long-distance relationship a painful separation or a trial separation?