The story
From cuck (“a cuckold or cuckquean: one who is married to an unfaithful partner”) + chair, alluding to a scenario where the person being cucked sits in the chair while watching their partner have sexual intercourse with another. The term was attested as early as the 2010s but first popularized as a meme in 2022.
Etymology from Wiktionary, CC BY-SA 4.0.