Garth Risk Hallberg said this quote

I couldn't understand; cheating was the one thing I'd told her all those years ago would be unforgivable. She knew, she said, but that was part of what had been confusing her, that I would even have told her that, as if she weren't an actual human being with the freedom to act, but some character in a scenario in my head. There was a quality I had of making the people closest to me feel lonely, somehow. Some essential cold withholding at the core of myself.