"She was me. Her face, her hair, her skin, her breasts. And the question suddenly became not who he was cheating on me with, but whether he had found my twin to be attractive on account of her likeness to me, or attractive on account of her difference from me, the only difference being, as far as I could tell, our identities. My personhood versus hers."
Lena forces her husband to fuck his mistress in front of her, then compares his energy to how he fucks her.