160. IV. THAT THE INCLINATION TO UNITE THE MAN TO HERSELF IS CONSTANT AND PERPETUAL WITH THE WIFE, BUT INCONSTANT AND ALTERNATING WITH THE MAN. The reason is, because love cannot do otherwise than love and unite itself [to another] that it may be loved in return, its essence and life being nothing else; and women are born loves, but men, with whom they unite themselves that they may be loved in return, are receptions. Moreover, love is continually working. It is like heat, flame, and fire, which perish if restrained from doing their work. Hence it is, that with the wife, the inclination to unite the man to herself is constant and perpetual. That with the man, there is not the same inclination to the wife, is because man is not love but only a recipient of love, and the state of reception is absent or present according to interrupting cares, according to the changes of heat and non-heat in the mind from various causes, and according to the increase and decrease of virile powers, in the body; and since these do not return constantly and at set times, it follows, that with men the inclination to that conjunction is inconstant and alternating.