Analysis of The Boyes answer to the Blackmoor

Black Maid, complain not that I fly,
When Fate commands Antipathy:
Prodigious might that union prove,
Where Night and Day together move,
And the conjunction of our lips
Not kisses make, but an Eclipse;
In which the mixed black and white
Portends more terrour than delight.
Yet if my shadow thou wilt be,
Enjoy thy dearest wish: But see
Thou take my shadowes property,
That hastes away when I come nigh:
Else stay till death hath blinded mee,
And then I will bequeath my self to thee.