Awh Lost, I am sorry this happened today. It must have been extremely hard to hear as you and your T are very close and get along so well. I can imagine it was hard for T too, to actually tell you this.
It is not happening imediately so you have time to process and to start to accept that no good thing lasts forever. T sounds like he has thought about this a lot. He is acting in your best interests and encouraging you to be independant and he thought you what is is like to have a positive role model in your life. Its not over yet and it might not be over for another ten years (hopefully) So please don't fret just yet and concentrate on the good things about therapy