The right "AS IF" attitude comes from imagining that she would think their is hope. When you assume the worst, you behave accordingly and create the worst.
I realize you can read lots of things on the board, but one man's good advice is another man's disaster. Detaching and dropping the rope, while common advice are not DB techniques. The LRT is. And that means pull back, as Sandi2 has described, and not initiating as your coach as described.
It doesn't mean detaching and dropping the rope aren't ever good ideas and can't be part of the LRT, but they are not good onesizefitsall advice.
Detach: can mean completely separate and go another direction, and it can just mean stop being so attached. It means various things to various people. The problem with this advice is if being detached was the problem to begin with, this can be disastrous advice. Pulling back is good advice for you, completely detaching is not good advice for you.
Drop the rope: It means: stop doing the work in the relationship. It has been interpreted as move on. Either way, this is not good advice for you. You need to be ready to do work as your coach has described.
Validating: When you are validating, you are not actually validating feelings. You are validating that she is important, and therefore you care what her feelings are. Agreeing or disagreeing isn't the issue, her feelings are what they are. Just listen to her experience and work to understand it. Don't worry about voicing your disagreement. That comes IF SHE ASKS. And IF SHE ASKS, you simply say no. And drop it. That was another piece of advice I received from Michele back in the day. It served me very well.
As you described, you have a lot of fear. Don't. Trust in the love that you have. Trust in what you have shared. Trust in the skills you are building.
What do you use in your job or hobby to center yourself when you are afraid?
sg Love is PATIENT, love is KIND, LOVE never fails / DB since 2001