These are all very good and valid points: if you want to work with her through this, you may get closer again but even if she improves, chances are extremely high that you will always play a supporting role. This may be right for you but if it is not, I don't think anyone would fault you for looking for a more healthy stable person for a relationship.
My dad did this: supports his wife with endless love in spite of issues cause by years of being raped by her father as a child. He gets the girl, so to speak, but although his wife has improved in some ways and become secure in their relationship which is 12 years strong now, his life is forever surrounded by drama. She is secure with his dedication to her, and she is also a prescription drug addict who has recently upgraded to morphine. He watched his brother die recently from years of herione abuse so he's no dummy. He has pretty much reconciled that he may literally love her to death, meaning she'll die from this before him although she's 9 years younger. He loves her, but to me this is a sad, sad way to live home life. I think part of him wants to be involved in a cause, to love someone who needs it, but it is not enough to save her and this is the price he pays for this relationship. He chooses to do this. I wanted to give you a glimpse of what deep issues like this could mean for you. 'Tis your choice.
If you choose not, there is love without drama. My husband and I are finishing up our 4th year and we enjoy a relationship with very little stress. It is easy to be married to him! Good luck.