I don't think you should get married at this time. I understand it's a big deal to change everything around, and a bunch of people may be upset, or whatever, but this is something you need to work on, find out about, and understand why it's there and where it comes from before making such a big commitment. You have to understand that there is not a chance that things may not work out forever, as is a risk all that marry take even if they are greatly in love, and otherwise feel well not only with their partner's 'skin' but surely their very own themselves.
But your current set up, and the way you are feeling, and also about her, and your obsessions, and all that...it's a disaster, and even that is an understatement.
I just hope you don't hate her and yourself so much that you feel the need to punish both of you.