Lou, If the spending is your major issue in the marriage, then why do you continue to bail her out? Why not keep completely seperate accounts and each be responsible for paying certain bills? If you did not know about her spending, and she was totally responsible for paying for her purchases, would it ease your mind?
I agree that her spending is wildly out of control. I think, though, that you are enabling her to continue this form of self medication by providing her with the means to do it. Set some boundaries on what you are willing and not willing to do and let the chips fall where they may.
Also you hinted around at some changes she would like to see you make...what steps are you taking to make that happen? Are you willing to make any changes for your M, at this point?
Just trying to get a handle on your situation and wanted to check in with you!