What does Marvell say about the nature of perfect love?

Marvell say about the nature of perfect love

In his attitude to love Andrew Marvell belongs to the school of John Donne. Like Donne's his love poems centre round fantastic and far-fetched conceits and the physical  aspect of  love.

Like Donne, Marvell blends passion with intellect and reason. While he expresses his passion of love he uses witty and intellectual conceits and logical arguments. "The Definition of Love" is a notable example of the argumentative love-lyric. The theme of the poem is the nature of perfect love which exists between the poet and his beloved. The poem begins with an intellectual conceit. He says that his love was begotten by Despair upon Impossibility. The birth of this kind of love is a rare event. This love is the offspring of the marriage of Despair and Impossibility. Only resolute Despair could have produced such a divine love. 

In the case of a love like this, Hope would prove to be utterly vain and futile, because this love can never be achieved. The poet could have achieved the fruition of his love, but Fate drove iron wedges and placed itself between him and his beloved. In the next argument the poet-lover complains about the jealousy of Fate to the perfect lovers. Being jealous of their true love, Fate did not allow their union, because their union would mean the ruin of the power of Fate. Now the poet is far away from his beloved as the two Poles are from each other. This love can be fulfilled only if the earth undergoes some new convulsion and if the would is cramped into a planisphere. Then the poet compares his and his mistress's loves to two parallel lines which can never meet if stretched to infinity. In fact, these lovers can never come together although they are the pivot round which the whole world of love revolves. 

Finally, by means of a metaphysical conceit, the poet describes the love between him and his mistress as the conjunction of the mind and the opposition of the stars. This love represents the union of minds, not of bodies, and it signifies the opposition which exists between stars situated opposite to each other. The whole poem is thus kind of logically developed argument in which the passion itself is almost forgotten and the speaker's chief concern is to establish the utter hopelessness of true love. We can even say that the prevailing mood of the poem is one of despondency, despite the feeling of calm contentment at the end.