Hmmm, Xue, I think you hit on something and may not realize it.
She loves to teach you things.
Can you apply this to your physical relationship (or lack-there-of).
Perhaps she feels you are so experienced sexually that she has nothing to teach you in that regard.
Wouldn't it be a great challenge for her to think she could rock your world in a way it hasn't been rocked. You know she needs to do the pursuing, she needs to feel like she's behind the wheel...