There's a good chance she won't go if you just make up your mind that you will have a good life with or without her.
Problems in my M probably started out like yours, but my W had a lot lower threshold for being taken for granted, and she had way more non-reality based magical thinking and codependency issues, so we got into problems sooner, and she had an (imaginary to everyone but her) EA that has really, really complicated the whole mess, and she keeps saying she is going to leave, and I am ok with that if it happens, but she keeps not going.
When I tried to reason with her, asked her to stay, and so on, she went further into fantasy land of a life that is going to be so much more wonderful without me in it, and her resolve hardened.
Now that I know that my life is going to be good no matter what happens, she is not so sure about things and keeps opting to stay (not saying that's neccessarily the best thing in my case, but I am still trying to figure out--after all of this--if she is cut out for the hard work it takes to get a M back on track).
I don't think our situations are similiar, but I do think that when you regain your confidence, stop resisting her, start improving yourself, and then start trying to figure out what you want instead of making it all about her, the situation is going to be very different. Not that everything will be fixed then, but maybe that's when it's a good time to consider MC?
M-47,W-40,No kids D-filed 5/27/2010 Piecing - 10/21/2010 -=Soon to be banned=-