rukkyg

First let me say that your view of yourself and my view of you contradict. You say that you pick on yourself a lot. I see that you feel to be superior to others. This isn't necessarily a bad thing.
You even say that you always think you're right. You took her out of her relationship, imposing yourself on her. She took your dominance and fell in love with it.

You say "to her credit," as if 1) her becoming catholic is a good thing, and 2) she has done a lot of things that didn't earn her credit. However, from your narrative, I see that all she has done is try to totally devote herself to you and do everything she can to make herself seem worthy to you.
Women in abusive relationships usually come from a family where their father was dominant and abused them, emotionally or physically. They then grow to depend on this abuse. However, they also begin to think that they deserve the abuse, and that it's their fault they're being abused. She obviously thinks this way now because she's trying to change herself to make herself worthy to you. Her mind is reacting in the way it knows how, as if it's being abused.

However, there are plenty of healthy relationships where one person always thinks they're right, and may act the same way you are, so I don't see anything particularly wrong with your behavior. However, you can not allow the current situation to continue because she is in the mindset of being abused. Unfortunately, breaking it off will probably seem to her to only be the ultimate abuse, that she has become so unworthy in your eyes that you are no longer willing to be with her.

I see two options:
1) Stay with her. Seek help. Have her work out her issues.
2) Leave her. Make it abundantly clear of how you see the situation and that you don't see her as a horrible or unworthy person, just that you two don't work together. It would probably be a good idea to help her with the therapy stuff even if you're breaking up with her. At least this way, you won't be in a relationship you don't want to be in.