For me it comes back to the fact that she started having sex with him back before she had to. There were always HUGE consent issues involved, and to my mind this has never been a healthy thing for her, but it's not like he pushed something on her that she didn't want. It's only when Stan killed her friend that she even became clear in her own head about where her loyalties really lay. So now she's playing him, but she's what she's using to do that so easily and so well is their earlier, real connection that she actually did feel.

-J