Hi,
So sex in dreams does not necc mean sex.
So, I am guessing that rape may be a similar thing.
Maybe the content in your dream was your t raping you, but that does not actually mean rape or that you are seeing him as a rapist or abuser.
It may symbolize merging or intimacy being mixed with fear and lack of control.
I agree with the other posters in that it would be great for him to work with you to unravel this. In many ways this could be progress and looking at this dream symbolically in the context of transference could psychologically move you forward.
I can see why he does not want an abuse or rape association and perhaps he is struggling with some reverse transference over helping you if he is male and you are female.
And honestly therapists are human too.
He may be able to see that he can work thru this and that ultimately this dream does not signify that he is being aligned with abuse, but more you are projecting abuse onto him, which is different.
Projecting abuse is an act of therapy or healing, or it can be in the right context.
For you to dream this is your subconscience wanting to process this by putting the trauma experience onto a safe persona. It is like hanging your coat on a hook. The coat is your trauma and the hook is your T, he is "holding" and reflecting the trauma so you can process it.
This happened possibly because you have developed enough trust which is also why his response to having you work with a diff T may be upsetting.
My T is very psychodynamic, and that's where my thoughts on this stem from.