Man has identity crisis because he realizes everyone he's ever met has a different perspective of who he is

I saw this book mentioned in some subreddit a few weeks ago -- I thought I had the comment saved, but I suppose I forgot. I think the conflict begins when his wife comments on some physical feature of his, that he disagrees with. I believe this launches his identity crisis, which might result in a descent into madness, as he realizes there is no "real" version of himself. If anyone can help me, I'd be super grateful!