I can relate to your post, especially the last paragraph...'an illusion of being part of someone else's life'...I feel like this sums up my relationships with people, including my T.

I don't know how or why it's like this. Sometimes I feel really close to people, friends or work colleagues or my therapist. Then stuff happens and I can see that I'm not really a part of their life at all, and it was all quite one sided or just in my head.

I have felt close to people at work and with people I volunteered with, but as soon as I stopped working or volunteering there, people instantly forgot me. It would probably be the same with my T. I think he forgets about me in between sessions, or he says stuff like 'all my clients are in my thoughts...' whatever that means. I think it means I'm not special to anyone, but I wish I was.

Sorry you experience this feeling too, it is not nice at all.