This is one of the central theses that M. Scott Peck puts forth in his best-selling pop psychology book The Road Less Traveled first published in 1978. He expertly disentangles the concept of true human love from the more primal physical love using a variety of case studies from his actual practice. The reasoning extends from the simple premise that loving someone means wishing the best for them, not simply fulfilling one's own needs.
Human love is something above and beyond the physical and emotional love of which we are all intuitively familiar. After all, animals may 'love' us for feeding them, just as we may 'love' them for companionship. But most would agree that there is a potentially greater element to human love; the love that stems from conscious reason and logic. Empathy provides us with a greater capacity for love. Awareness of another person's thoughts gives us the ability to take measured action on their behalf rather than slavish instinctual action.
True love is not blind service, but a strong commitment to the person's ongoing spiritual growth. As such, true human love is never a cut and dried issue. One's full experience and knowledge of the individual must always come to bear to best approximate what the result of any action might be. Romantic love is not a necessary part of the equation, in fact it may make love seem deceptively easy, but human love is a sustainable effort whereas romantic love is unpredictable and highly subjective.
M. Scott Peck's definition of love is attractive because it meshes well with the human experience. It acknowledges that love is not always easy, but that it can consistently produce good results. It is a useful definition, because it removes the consideration of instinct from a topic which has traditionally been mired in subjectivity. A very good read.