On your original question, it's really hard - there is no magic. The main way I would suggest to believe in that 1% is to try (and know it's sooooooo hard) to have less black and white thinking.

So reading your posts I believe he did care, he did have fun with you, did enjoy your company. It happened. But now he has other priorities that for him come above bending the best practice to see you outside the therapy framework. That is his decision in the context of his life. It does not negate what went before.

As I read it you think it does and that is what I see as the black and white thinking. I do that, struggle hugely with it so no judgment here. But it is a cognitive distortion.

But I can't tell from your posts whether you feel and rationally believe it or whether you feel it but know it's not the full picture. For me I try and work towards the latter and that would give me the 1% belief.

Hope this helps but if not tell me to bugger off! Only want to help you.