I forgot to ask - did you open the letter yet? There might be something in there to give you some peace.

For what it's worth, even with a 3 way phone convo, I suspect you would not have gotten the real answer especially in the presence of a third party. They 'why's' of the reason she thought termination was best for you or best for her, are feeling based and likely difficult to articulate, especially to someone with heightened sensitivity that's going through a hard time. It's like asking why you love someone - you can give all these squishy reasons, but at the end of the day the feeling just exists even when it doesn't factually make sense. You had, and likely still have, a strong connection to this T that nobody except the two of you will ever understand, and like I mentioned, the termination was likely as enigmatic as the relationship itself.

Not to try to instill some kind of false hope, but maybe once you and T have had a cooling off period, you may be able to approach her a year, or 2 years later and get some answers. I recently read Love's Executioner, and there was a chapter about a T relationship gone wrong - where the T had a personal relationship with the client, then cut contact all together and it tortured the former client. The 'behind the curtain' reason was so out there and strange and ALL about the mental state of the T... It's just so hard...