I think this is because love possesses spirituality . The spirit is the agency that preserves the shared meanings of language. If the Father is the center as inaccessible Being and the Son is the center as victim, the Spirit is the center as the locus not of figure but of meaning.
Spirituality is communication in and through the transcendental guarantee of the spirit.
In the Christian Middle Ages, the idea that my love for another human being provides in its very specificity a model of my love for God gives rise to a new human-based spirituality based on the nearly universal experience of love. In the richness of its reference to our common origin, it is ultimately immaterial whether the object of this love is human or divine. But the spiritual life of society as a whole is not organized around our experience of finding God in our beloved's eyes. The locus of spirituality for most remains organized religion . The various religions incarnate historically different insights into the sacred basis of the human.