From A Preface to Paradise Lost, pages 123-24:

People blush at praise—not only praise of their bodies, but praise of anything that is theirs.  Most people exhibit some kind of modesty or bashfulness, at least at the beginning, in receiving any direct statement of another human being’s affection for them, even if that affection is quite unrelated to sex or to the body at all.  To be valued is an experience which involves a curious kind of self-consciousness.  The subject is suddenly compelled to remember that it is also an object, and apparently, an object intently regarded:  hence, in a well-ordered mind, feelings of unworthiness and anxiety, mingled with delight, spring up. There seems to be a spiritual, as well as a physical, nakedness, fearful of being found ugly, embarrassed even at being found lovely, reluctant (even when not amorously reluctant) to be found at all.  If this is what we mean by shame we may, perhaps, conclude that there was shame in Paradise.  We may, I think, go further and suppose that even without the Fall sexual love would have excited this kind of shame in a specially strong degree; for in sexual love the subject is most completely forced to realize that it is an object.  But that is quite the furthest we can go.  All that part of shame which is specially connected with the body, which depends on an idea of indecency, must be completely ruled out.  And I do not think it can be ruled out while we are reading Milton.  His Eve exhibits modesty too exclusively in sexual contexts, and his Adam does not exhibit it at all.  There is even a strong and (in the circumstances) a most offensive suggestion of female bodily shame as an incentive to male desire.  I do not mean that Milton’s love-passages are objectionable by normal human standards; but they are not consistent with what he himself believes about the world before the Fall. 

…It is conceivable that Milton himself might have succeeded if he had said nothing about angelic love and treated the loves of Adam and Eve as remotely and mysteriously as those of angels.  Even a protestation (and who could have written a better one?) that he was now approaching the unimaginable, whatever actual treatment followed that protestation, would have gone far to save him.  The trouble is that the poet hardly seems to be aware of the magnitude of his own undertaking.  He seems to think that by twice using the word mysterious in this connexion [sic] (IV, 743, and VIII, 599) he excuses his very un-mysterious pictures—or to hope that when he writes ‘half her breast Naked met his’ we shall be able, without further assistance, to supply for Adam an experience both very like and totally unlike anything that a fallen man could possibly feel!