@steve24,
Firstly, welcome to A2K. You have my sympathy with this relationship. It's great being close but only if you're both heading towards a direction that works for both of you.
You know so many people here might offer you some sage (and not-so-sage) advice, but the discussion wouldn't be as valuable as hearing it from her. I would suggest strongly to discuss it directly with her.
I'm not certain if this is what is going on but perhaps she needs to stop sending you these mixed messages. She can't have her cake and eat it, too.