It is no crime to be passive. In fact, many women are brought up to be this way. It is frustrating to be passive, however. There is a better way. Learning to become assertive will mean that you'll get to learn how to stand up for what you want, but to do so in a way that is not aggressive or attacking.
Assertiveness is the way to go.
I hope you'll explore more on this subject. I don't know how to help her or what's wrong, we both come from good whole families. I know all she wants is a happy family. I'm not the best to live with and can be demanding but am willing to change. Perhaps send her some flowers to show you care.