The cliche "distance makes the heart grow fonder" is only partly true. Because all too often distance will seed and sprout disinterest. And unlike hate, which is never separate from love, indifference is its truest adversary and antithesis.
Apathy allows for selfishness. Whereas love requires we put aside common sense and instincts for survival, to value the well-being of another as paramount. I would say that many of us never love without condition. So we spend lengthy portions of our existence too timid to love as we should. And then some of us will forever mistake infatuation and lust for weightier connections.
We are held back by paranoiac whispers from internal Iago-esque voices, which spin fear-laden fictions and warn us against lifting that last bracing foot from the ground, lest we be irrevocably swept up by a tempest of adoration, and lose ourselves completely.
Loss is all the more frightening to us (particularly we "post-modern" Americans) who have only ever coasted along the downward slope of radical individualism. Those of us who make the assumption we are self-determined and free are all too often the least liberated...especially in love.
PS - I reserve the right to change my feelings and/or opinions about this subject matter and anything else I may say (or not say) without apology.