She was not Charlotte.
It's the one thing he was certain of. The woman who had come back after the detectives had visited him, while looking every bit like his wife, was not her. And even though it took him a day or two to notice, now he can't stop noticing everything that's changed about her.
He went to his therapist about it. Tried to explain that the woman living in his house was not his Charlotte but it came out sounding crazy. His therapist, Dr. Martin, God bless her and her patience because he knows he sounds crazy, listened to everything. And when she had explained that near death experiences often resulted in behavioral changes, he was tempted to believe her. But he knows that's not the truth.
For one, his Charlotte stopped sleeping with him a long time ago. Not that he is complaining about the change but he knows it's not because he took that detective's advice and started taking better care of himself (even though he kept the crocs, his kids liked the colors and they were comfortable).
Secondly, it was like everything was new to this new not Charlotte. She studied every little thing like it was the first time she had seen it. She didn't even seem to know the names of their kids at first. But she was trying. More so than his Charlotte ever had. And it was endearing to see her figure things out and the sheer determination in which she approached everything. Though this new Charlotte seemed to be basing everything she did on advice from a 60s housewife manual. He's already become use to the burning smell that lingers in the house from her cooking attempts. Something his Charlotte would never have done.
And that was just the tip of the iceberg regarding how this new Charlotte was not the woman he knew from before. He's started noticing the little differences that prove that this woman is not his Charlotte too. The way she moves, the way she talks and the inflection in her voice, her likes and dislikes, even her most basic habits have all changed. It's like watching an actress play his wife and he finds it as fascinating as it is strange.
But even though he knows that this person inhabiting his wife's body isn't his Charlotte, he doesn't mind because he's starting to prefer this Charlotte.