Conjugal love, or the friendship of spouses, can persist even after sexual desires have weakened, withered, and disappeared.
It is love rather than sexual lust or unbridled sexuality if, in addition to the need or want involved, there is also some impulse to give pleasure to the persons thus loved and not merely to use them for our own selfish pleasure.
Theories of love are found in the works of scientists, philosophers, and theologians.
If one wants another only for some self-satisfaction, usually in the form of sensual pleasure, that wrong desire takes the form of lust rather than love.
I wonder if most people ever ask themselves why love is connected with reproduction. And if they do ask themselves about this, I wonder what answer they give.
One of the aims of sexual union is procreation - the creation by reproduction of an image of itself, of the union.