It seems like the first thing you should do is get on the same page with your girl friend or break up. It will be super awkward to start talking about finances, dreams, plans, long term goals, expectations for lifestyle, etc. But, it doesn't get any less awkward. If you are serious enough that you let her charge things on your credit card, loaned her money, and have heard her opinion on what house to buy, you are serious enough to talk about why you want to save and how you want to live.
It seems to me that nothing effects your financial success or failure as much as the person you live, eat, shop, and raise children with.