The Blue Window by Suzanne Berne

Greta lives with her friend Sabine in an ancient Dutch farmhouse in Hudson, New York. The house is unrenovated, uninsulated, and full of bees. Greta spends her days transcribing therapy sessions for a sex coach who calls himself Om. She becomes infatuated with his newest client, a repressed married woman she affectionately refers to as Big Swiss.
One day, Greta recognizes Big Swiss’s voice in town and they quickly become enmeshed. While Big Swiss is unaware Greta has eavesdropped on her most intimate exchanges, Greta has never been more herself with anyone. Her attraction to Big Swiss overrides her guilt, and she’ll do anything to sustain the relationship…
“A fantastic, weird-as-hell, super funny novel” (Bustle), Big Swiss is both a love story and a deft examination of infidelity, mental health, sexual stereotypes, and more—from an amazingly talented, singular voice in contemporary fiction.