You have the right to get angry, I don't think you should feel bad. She's so absorbed in her own confusion, she needs to know that she's affecting you. There's nothing wrong with that.
I don't have any advice...but I think something that seems to be happening with her is that she thinks she needs to be "alone" as in living apart from you and OM to figure out "the source of her ambivalence." She's made comments that her mother thinks she needs to get away from OM (so that's good, her mom seems to see the situation for what it really is, that he is influencing her).
So... she feels constant confusion depending on who she's talking to...there's you, OM, mom, psych. at a minimum. She probably changes her mind 10 times a day. I remember times I wished I could just separate from my H just to be alone and have the pressure off of me so I could think. You don't sound like him though, but she could still maybe be feeling that way.
Her doctor is trying to get her to get to the bottom of her feelings, and maybe she thinks she can't do that when she is reacting to everything around her. She said it herself, she hates herself, and you're right. She won't be happy with you or with him or by herself until she solves that. Even if she dumps him, turns back to you...you still have a big foundational problem if she remains like that. As I said, this current situation with the OM is a symptom of her problems not the cause.
Also realize there's an element of her thinking it's probably too late considering what SHE'S done.
anyway, I have to get to work...have a good day and don't be so hard on yourself. I bet you are usually too hard on yourself! Have you found an IC yet?
