you are NOT a monster. if you were, you would not be having this conflict. and it is a struggle that many - if not most - of us deal with: the difference between the higher, idealized hopes for ourselves (what we think we "should" be) against the damaged, lower, darker, unwanted attractions that are the product of the abusive esperiences (the real or exagerrated - often self-loathing - version of what we think we "are.")
remember - though you feel dirty and transparent - others can't see inside you the way you fear they can. don't despise yourself - you are a work in progress. and all of us here know what a good guy you really are - no matter how you feel.
"That you are here - that life exists, and identity; that the powerful play goes on and you may contribute a verse. . . What will your verse be?" Robin Williams as John Keating in "Dead Poets Society"