I say "break up" with this t in whatever way is best for you. This isn't about him, though in crossing the boundaries he made it that way. I think since you aren't one for putting people in bad positions you run a higher risk of being coerced into staying if you terminate in person. A cancellation and thank you text seems a safe idea, but, only you know what is the best choice for you to make here.

I couldn't agree more with you when you say there is a good reason as to why therapists and clients shouldn't be friends (like 99% of the time). Therapy becomes ineffective as the therapist is now serving his/her needs first, not the clients. The way I see it, a t that willingly crosses the lines with a client knowing the harmful and mind f##king effects a friendship has on that client has to be "off balance" in some way themselves. Only you can put an end to this. Know that your decision to end this relationship is the best decision for you and for him because whether he can admit it now or not, this relationship is wrong for him, too.

I applaud you for taking your power back. It will not be easy to cut the ties with this guy initially. Hopefully, the relief and inner strength that you will find from closing this chapter in your life will be so significant that any heartache will quickly subside. Best to you and keep us posted!