This is like putting a Band-Aid on an amputation as it doesn't feed any aspect of the relationship except physical desire. Thus, the rest of the relationship doesn't get nurtured. We like to be around people who are healthy and who care for us. Our significant others from so far away cannot do these things for us. I am just saying that a natural propensity exists for college-aged men to seek out a means to fulfill their sexual desires.
Men often mature more slowly than women as well, further complicating the problem.
Control develops out of Fear and Fear develops from a lack of faith. People often fear that they will lose what they have or never get what they want. The more a couple tries to control each other, the farther apart they will drift and the less attractive the relationship will appear. Finally, in a cruel twist of fait, if a couple survives the long distance part, they still may break up when they reunite and move back closer to each other as they have gotten so proficient at being apart they find they are no longer good together in the same place. They got so used to being apart that they have lost the ability to be together.