If you don't want to do it ... and if you really know that's what you want ... you don't have to ask for it to be the last session. You can just say it. You can even do it graciously if that makes you feel better, thanking her for her help and all that.

It alarms me that you say you react to her like you do your abusers. That's not something that can be worked out in a remaining session or two.

If you think you might struggle through the holidays, you might rethink this, but otherwise you can just end it on your own, on your own terms.