https://www.mangago.zone/read-manga/the_third_perspective/ I’m not sure exactly but this sounds similar
if you mean a physical therapist and not a mental health therapist, i think it might be one of these two. i only skimmed them and haven’t fully read them, so sorry if they’re not exactly what you were looking for!
https://www.mangago.zone/read-manga/jinx/
https://www.mangago.zone/read-manga/blind_play/
Just random ones that sounds similar.
https://www.mangago.zone/read-manga/aporia/
https://www.mangago.zone/read-
https://www.mangago.zone/read-manga/love_me_doctor/
https://www.mangago.zone/read-manga/ten_count/
https://www.mangago.zone/read-manga/secret_therapy/
https://www.mangago.zone/read-manga/interview_with_a_murderer/

Okay, so, I read this story a long time ago and I have very episodic memories of it, but really want to find it. It's about this sort of therapy (?) or session - based practices and at first, the therapist doesn't really want to or has this boundary to not have sex with the person, but then as time progresses, they do(?). The therapist is blonde if I can remember correctly... It reads as a BDSM dynamic and yeah. It was full colored. I know it's vague, but I just have pictures in my mind, no plot and character specifics.