What will you do when you find out that the person sleeping next to you every day is not your husband?
Call the police? The police will not open a case for investigation just because you said, "He has changed his walking posture."
Falling apart? You will alert others and never find the real person.
You can only pretend that you didn't notice anything, watch him wearing your husband's pajamas, smile at you with your husband's face, sit in your husband's seat, and drink red wine that your husband will never touch.