canonsigil started following So how did Tyrion find out about Jaime and Cersei?
I know Tyrion is intelligent but how did he find out about the twincest? It seems like he's been aware of it for some time in ACOK. I've heard some say he knows because he lived with them, but at the time Tyrion was fairly young so I don't think he could've noticed anything. Is it possible that Jaime just let it slip one day? I wouldn't be too surprised as Jaime doesn't really care about keeping the secret. However, this still seems pretty unlikely.