C.s. Lewis said this quote

The event of falling in love is of such a nature that we are right to reject as intolerable the idea that it should be transitory. In one high bound it has overleaped the massive of our selfhood; it has made appetite itself altruistic, tossed personal happiness aside as a triviality and planted the interests of another in the centre of our being. Spontaneously and without effort we have fulfilled the law (towards one person) by loving our neighbour as ourselves. It is an image, a foretaste, of what we must become to all if Love Himself rules in us without a rival. It is even (well used) a preparation for that.