I don't know if your decision is right with the limited amount of information you've provided. Have you spoken to her about doing more to show you that she appreciates and values you? Explained to her how down-trodden you feel as there is no show of affection or appreciation. How the lack of affection and the extent of her apathy has you contemplating leaving for good? Have you given her any chance whatsoever to remedy things?
If you have spoken to her about this and given her meaningful ideas on what it will take to make you feel happy around her and she still isn't doing anything but use you for your financial support then yes, You are definitely making the right decision to leave.
“The willingness to accept responsibility for one’s own life is the source from which self-respect springs.” ~Joan Didion