I'm so sorry you're dealing with this.

I've had to ask for empathy from my T before, where it just seemed like an obvious, easy place to give empathy and he just...didn't. (I started to type up a detailed account of one example--when my D had Covid just before a family vacation a couple years ago--but realized that probably wouldn't be very helpful to you.) I've actually said things like, "I could really just use some empathy here." Or "I'm really just looking for support."

If you haven't directly said things like that to her, I would. I know it can be difficult. But I think it's better ultimately than holding it in and not getting the support you need and deserve. I'd basically tell her what you said here. If it's too difficult to say out loud, maybe write or type it, then hand it to her at the start of session (or email, but I know you've had some issues there): "I explained the facts at the time, but R has yet to acknowledge the impact of this information.

I would appreciate hearing her say something to the effect of 'I'm sorry you now know this.' or anything that indicates a level of understanding...but having to ask for it feels weird, when it has always been a given in our relationship.

I'm having extreme difficulty with the sense that she's forgotten this destabilising information."

I hope she can give you support and empathy.