I do the same to my husband and I feel horrible!! I just started counseling because I said enough was enough! He stand behind me 100% and he is a loving caring husband just as you are. If she is not in therapy maybe when she feels good or after an out burst you can offer to bring her and be there with her even if you don't go in the room with her you can wait for her...let her decide..some thing she may not feel comfortable talking about in front of you. Also finding the right therapist is the key also. If she doesn't like it suggest to try another till she is comfortable.
Good luck and keep loving her she needs it!