Spenser chose to spell his name this way, and he generally tried to embrace archaic spellings, or his notion of them, in his work. Some interpret this impulse towards archaism -- steeping himself in tradition -- as a response to self-consciousness.
Spenser, "although always a friend and admirer of Oxford" (Ogburn and Ogburn 28), had Puritan leanings and belonged to the Sidney group (along with Dyer, Greville, Raleigh, Harvey, and in the later decade Daniel, Drayton, Campion, Greene, and Marlowe (Ogburn and Ogburn 60, 183). They were called the Areopagus literary club, opposed to the Euphuists, led by Oxford and including especially Lyly, Munday, etc. The Sidney group intended to explore the possibility of English poetry based not on rhyme and accentual meters but on something akin to Latin hexameters and the exact quantity of syllables.
In The Shepheardes Calender, which takes up the Elizabethan fad for pastoral (explored a bit in As You Like It and thoroughly manifested in the 1600 collection England's Helicon), is introduced with a poem "To His Booke" which itself starts with a Chaucer paraphrase (from Troilus and Criseyde). Rosalind represents Anne Vavasour (Ogburn and Ogburn 193). "August" supposedly depicts Perigot (Oxford) vs. Willye (Sidney) in dialogue (Ogburn and Ogburn 190). "October" contains several E.O./Oxford/Shakespeare connections.
The unidentified "E.K." who supplies introductions and other editorial matter to The Shepheardes Calender sometimes seems to be Spenser himself; Edmundus Kedemon is a translation of Spenser's name into Greek (Green 5). But there has been speculation that E.K. is the Earl of Oxford, and that "E.K.'s role is like that of the sly pilgrim Geoffrey in Chaucer's Canterbury Tales" (Green 6).
Shakespeare's famous Sonnet #130 may be "glancing playfully" and in a mocking vein at Spenser's Amoretti #9 and #64, with Vavasour as Spenser "dark spright" (Ogburn and Ogburn 906).
#1 (An address to the work itself.)
#37 (Hair, bad!)
After long stormes and tempests sad assay,
Which hardly I endurèd heretofore:
In dread of death and daungerous dismay,
With which my silly barke was tossèd sore,
I doe at length descry the happy shore,
In which I hope ere long for to arryue,
Fayre soyle it seemes from far and fraught with store
Of all that deare and daynty is alyve.
Most happy he that can at last atchyue
The ioyous safety of so sweet a rest:
Whose least delight sufficeth to depriue
Remembrance of all paines which him opprest.
All paines are nothing in respect of this,
All sorrowes short that gaine eternall blisse.
#67 (A twist in the end but still very unpleasant language and implications.)
#68 (I think maybe that's a different kind of love....)
#75 (Insists on the immortalizing properties of his poetry.)
The woman addressed in Amoretti responded to the poet's suit and so here they are, with a rare instance of courtly love leading to if not absorbed into marriage. Somewhere around line 241, the ceremony takes place, but we've got an absent center, perhaps not inappropriate to te experience, for at the very start of the next stanza the ceremony is done, passed by perhaps in a hyperconscious swirl. An aubade is incorporated too.
Green, Nina. "Who Was Spenser's E.K.? Was He the Seventeenth Earl of Oxford?" The Oxfordian 1 (1998): 5-25.
Ogburn, Dorothy and Charlton Ogburn. This Star of England. Westport, CT: Greenwood Press, Pub., 1952.
Spenser, Edmund. The Shepheardes Calender, Amoretti, and Epithalamion. The Norton Anthology of English Literature, Volume 1. 8th ed. NY: W.W. Norton & Co., 2006. 705-713, 902-916.