In most instances, the distance involved in a long-distance relationship is a factor in the success or failure of that relationship. Many individuals have been involved with another person who resided in a different region, and for whom long drives or flights were a matter of routine. And, in some instances, the distance was not a factor. A couple with one residing in Washington, D.C. and the other in Philadelphia or New York are not confronted with an insurmountable problem, as drive and flight times are short and airline schedules highly condusive to that particular commute, especially for purposes of weekend visits.
The longer the distance between parties, however, the more physically and mentally exhausting the relationship often becomes over time. One or both parties will eventually develop a sense of resentment regarding the requirement to commute regularly to the other's location -- even when a reciprocal arrangement is established alternating responsibility for the travel.
In addition to the stress usually associated with traveling, long-distance relationships invariably impose substantial financial burdens on both parties due to increases in airfares or in gasoline prices, as well as factoring in wear-and-tear on one's automobile when driving is the primary mode of transportation. No matter what mode used, however, costs accumulate over time that can prove prohibitive.
There is no question that, in the current era of "facing" over computers, the ubiquity of cell phones, and other means of communication, that long-distance relationships no longer involve protracted periods of non-face time as was historically the case. The lack of physical contact, however, is often missed and eventually even communicating through video via computers becomes an unsatisfying way of maintaining the relationship.
As noted, some couples successfully maintain long-distance relationships. For most, however, the greater the distance involved, the more physically and emotionally demanding the relationship, and the greater the willingness to eventually go separate ways.