The Echo Wife

Sarah Gailey''s The Echo Wife is ΓÇ£a trippy domestic thriller which takes the extramarital affair trope in some intriguingly weird new directions.ΓÇ¥--Entertainment Weekly
IΓÇÖm embarrassed, still, by how long it took me to notice. Everything was right there in the open, right there in front of me, but it still took me so long to see the person I had married.
It took me so long to hate him.
Martine is a genetically cloned replica made from Evelyn CaldwellΓÇÖs award-winning research. SheΓÇÖs patient and gentle and obedient. SheΓÇÖs everything Evelyn swore sheΓÇÖd never be.

And sheΓÇÖs having an affair with EvelynΓÇÖs husband.

Now, the cheating bastard is dead, and both Caldwell wives have a mess to clean up.
Good thing Evelyn Caldwell is used to getting her hands dirty.