We show affection because we Love. In fact life itself is a longing to re-discover that love that we are. We marry because of love; we have children for the same purpose, and we drink, smoke; take drugs for the same idea.
All is a quest for the Source from whence we came, and we know this either intuitively, consciously or unconsciously. That is why, even in a long-lasting relationship, loneliness is always there. The Soul knows of its true Freedom and will not stop seeking until it's found. We are in Isolation from Love only because we came from Love, and all is a striving to return to that Love.
So whether its affection, killing, or fancy cars, all is motivated by a striving to regain that equilibrium which belongs to ALL: Love with a capital L. Showing affection is like politeness or morals and etiquette. They may or may not have much to do with the inner Journey, which ALL must take.
We sometimes discuss Love in categories, but seen from a Higher standpoint, there is only Love. It is only a matter of degree. The same Force that manifests in the life of the Seer, manifests in the affection of humans. Just vibrating, perhaps, at a lower level, or with less Light. ALL is in the One and ALL is One. Much peace.