The Couple Next Door

I should have returned this steaming pile to the library at the first mention of the Easy Amnesia trope.

https://tvtropes.org/pmwiki/pmwiki.php/Main/EasyAmnesia

Cardboard characters in an unnamed, generic city going through the motions of a mystery whose only reason for existence is to flatter the intelligence of readers who guess the “twists” about 5 minutes before they are made explicit.

I'll never read this author—though I'm sure it's a pseudonym because he/she is ashamed of their craven ripoff of The Gone Girl—again.