Read this off Michelle's Blog and thought of you.

People who say their affairs just happened aren’t necessarily intentionally trying to cover their asses or justify their behavior; they often truly believe what they’re saying. They simply lack insight or awareness of the ways in which their actions, however subtle, have created their current predicaments. But in the same way that affairs don’t just happen, neither does healing from betrayal. Unless those who have strayed look inward and take personal responsible for the paths their lives have taken, they will not be able to get back on track when they’ve gotten derailed. In my view, being unconscious just doesn’t cut it.

You're looking for her to share her personal responsibility of your marriages problems and her affair. She hasn't done that. I think when you sit and talk to her about how you need to HEAR it and FEEL it, that she will rise to the occasion.