Sri Aurobindo
Letters of Sri Aurobindo
Volume IV - Part 3
Sex is not a rational force; it is purely irrational, a power of the inferior, animal nature; you cannot therefore be rightly astonished if it acts irrationally without any justification or reason 
and without any other cause than its own habit and instinct. Moreover, this force as it is now acting in you with regard to X seems to be purely vital physical and physical in its character. It is not supported by your thinking mind or your rational will, these are opposed to its continuance; it has no emotional support, for you are no longer attracted by her or in love with her; the higher vital does not seem to be concerned, for neither beauty nor passion draws or drives you. But at this level of sex none of these things are necessary. The vital physical and physical urge of sex does not ask for beauty or love or emotional gratification or anything else; desire, repetition of vital-physical habit and bodily gratification (most usually, but not necessarily by the sex-act) are its motive forces. To set it in action nothing more is needed. Moreover, by mental and other rejections it has plunged down in the subconscient and is hidden there and rises suddenly from there. It is itself born from the Inconscient as a blind push of its dark force of Nature. It owes no allegiance. It can only be got rid of by a firm and persistent rejection, separation, detachment, not yielding to it by any act, refusing to take joy in it in any part of the being, until it is a dead thing and has no longer any motive or power of existence.