Behind The Knothole (1970)

The protagonist is a troubled and unpublished author who begins a complicated love affair with his new neighbour’s wife, Mia. They spend their days in romantic and poetic bliss, while Fin spends his nights tormented by everything he can hear that goes on and is said in Mia’s apartment through a curious section of shared wall. Mia moves and ends the affair but sends a copy of herself to continue the relationship with Fin, who can’t help but want the original Mia back.