I am very sorry that you need to let go of her, it always came across from your comments boldly that you have a strong relationship. I am also thinking that perhaps having much more than 2 months might actually turn counterproductive by prolonging this painful "limbo" period. Can you maybe see her more frequently than usual during the remaining time? Some people here say that they start seeing a new therapist already before the actual termination date with the old one, would that be helpful?

Painful as it is now, it sounds like your T has been highly committed to working with you, 12 years is a very long time. Unfortunately T's are not machines created to serve the clients no matter what, have no needs on their own etc... Maybe she has arrived at a stage of her life/career where she needs this change not only for financial reasons but for her own growth as a person? Of course there is nothing rational in how we react to and deal with loss so knowing she may have good reasons to end her therapist role is not going to soothe the pain much.

I think what I would do is make the rest of the time together as meaningful as possible, express my feelings to her so that they are out there and not held back so that they come back to haunt you long after the separation in destructive ways. I know it is hard since you probably don't feel very comfortable expressing negative feelings towards her and/or her choice, but perhaps your best interest right now to continue doing that? I recall from your posts that you had a tendency to express your thoughts and feelings to your T in creative ways -- perhaps something to do now about this as well?