To this day I still wonder about this, even 6 years after first finishing A Storm of Swords, when Jaime reveals to Tyrion that their father Tywin made him lie about Tysha being a whore.
This supposed reason Tywin lied, was because he thought Tysha was just after a piece of the Lannister fortune, which would've made her "no different from a whore." Something about this just never added up for me, because if that were the case, then he could've just paid her to leave Tyrion.
Is it possible Tywin actually tried to pay her to go away, but she refused because she actually loved Tyrion? Then because of this, Tywin made up the lie that Tysha was a whore, then forced Tyrion to watch as the Lannister guards sexually assaulted her, to teach him a "sharp lesson."
So do you think Tywin actually believed Tysha was after Lannister gold, or do you think it's more likely that Tywin just didn't believe Tyrion deserved to be happy?