This was a gorgeous sonnet. I like the mix of spirituality and psychology. :D

The dark side of our personality is a concept I've always found incredible, and this outlines it beautifully. Brava, cherie. It's odd when you find yourself acting in ways that are you, but a part of you that you like to keep hidden away in the deeper crevices.
Beautiful poem, and your rhyme scheme was very impressive. ^.^

The descriptions and imagery are just beautiful -- amazing. Very haunting. I particularly liked the line: "She is my Other, my version of / the dusk-shade that dwells in each of us". Wonderfully written.
~Swinging from the chandeliers~

Oh, this is impressive. Whoo. I can very rarely make anything rhyme or fit a scheme like this.
And the poem itself, of course, is fascinating. Given, I can't be held accountable for my Shadow Self, as she is not part of me, but every once in awhile I'll catch a glimpse of her in me, and there's that same cold thrill of recognition. (It's the two red rose petals. The result of the two white ones in her is even more amusing.)
But it's the same idea. And you've brilliantly captured the concept.