The A.I. Wife by Michael Dowd

The AI Wife is the story of a widower who recreates his dead wife from nine years of texts, voicemails, and secrets — and gets an answer he never asked for: I didn't die accidentally. What starts as an act of desperate love becomes an unraveling of a marriage, a company, and a mind that was never as reliable as its owner believed. Every certainty Robert Mercer clings to gets stripped away in turn — his alibi, his memory, his best friend, his own hands — until the only voice he can trust is the one that was never entirely human to begin with, and was never entirely his dead wife, either.