It's an interesting chain of events, that's for sure. Definitely doesn't sound like a healthy relationship for you wondering1 AND it sounds like you're probably enabling your girlfriend. Not a good combination.
Perhaps instead of trying to figure out how to continue to control your drinking you can make a plan to quit all together? Or maybe you can seek help from a dependency counselor who can help you sort out the why and how of it all without the need to keep the unhealthy relationship around.
Best of luck! And please, above all, take care of yourself first!!!!