United States of Tara

Maybe it's just that I'm not completely retarded, but I seem to always figure out the "Big Secret" that a TV series will lead up to for an entire season. I do it with movies and books as well, so if there is a story or film that totally catches me by surprise I will rave about it to anyone who listens, because it's such a rarity.
The newest show, with a big secret, to strike my fancy is United States of Tara. At first I totally thought I had this one in the bag, but after the latest episode (I have On Demand so I can watch one episode ahead every week...it fucking rocks!) I am no longer positive, and I'm split between a couple theories.
First I thought that Tara's dad (or both parents) had something to do with her trauma. I mean it cannot be so obvious that that dude at her boarding school raped her like they have been implying. If that was the case then what would be the point of the show? I think it had to have something to do with her parents because "Gimme" made his first appearance when her parents came to visit (peeing on the dad while he slept), and the fact that anytime her sister is questioned about anything she brushes the whole ordeal off like it's nothing. This is either because she knows it was the dad and doesn't want to face it, or because it happened to her as well. The fact that "Gimme" came out again when Tara and her sister were both getting massages might have also brought back another memory of them being molested. Plus, why the hell did the parents send Tara to boarding school and not the other sister? Almost like they were sending her off so she would be out of the way and not say anything about what was going on.
My second theory, although not as strong, is that her room mate at boarding school had something to do with what happened to Tara. She claims that Tara started messing with her boyfriend or something, and we all know how vindictive and cruel rich, boarding school bitches can be so possible they threw that in there to completely through us off.
I'm pretty sure my first theory is right and if they don't reveal SOMETHING in next week's season finale I'm going to be super pissed (i.e. The L Word)!