What I mean by that is you never pay for everything for her. You never do everything for her. You never give her more emotional support then she gives you. (By the way, if something tragic happens that doesn't give you a right to ignore her or go "I'm only giving 40% here, then you step up and be a man and guide her through the tough times). All things being equial you only give 40%.
Look at what you were doing. You gave her 100% emotionally and you got dropped and are now trying to figure out what happened. That is my point. Emotionally she's not hurt, because her emotional investment was 0%. She didn't need to put herself in the relationship because you did everything for her.