Ok, so what's so bad about.....

[SteveMB]

Possibly--but then looking at the complete sentence Jillian speaks, she says "[Wanda]'d never follow that monster of her own free will," which implies separation between Stanley's monstrousness and the possibility of Wanda being mind-controlled. Therefore he would still be a monster in Jillian's eyes even if Wanda were free-willed (and therefore just as much a monster as he).

That last sentence gets to what I think is the bottom line: Jillian really doesn't want to believe that Wanda would mistreat and exploit her the way she has. She explains it away by assuming that Wanda is under a loyalty spell, and thus everything bad that happens can be blamed on Stanley rather than Wanda. Thus, her resentment of any mistreatment at Wanda's hands is transferred to Stanley -- on top of her perfectly reasonable anger at him for destroying Faq, that makes him a "monster" in her eyes. The rationalization is somewhat self-reinforcing -- the more blame she transfers to Stanley, the more of a "monster" he becomes, and the less believable it is that (her idealized mental image of) Wanda would follow him voluntarily.

In the immediate aftermath of breaking free of Wanda's control just before the battle over the lake, Jillian was angry enough to vent at Wanda (the "I hope you can see this" comment I noted earlier). However, that didn't completely destroy the above rationalization in one swell foop. Confronting Wanda face to face, she is still not entirely sure of herself (note all the pauses at first, before she gets to the point) and still in denial about Wanda's culpability, explaining it away as Stanley's fault ("She'd never follow that monster of her own free will.")