Yeah. I’m so sorry that happened to you. I get it because a very similar thing happened to me. I later understood it as not only about the therapist’s incompetence but as part of a troubling dynamic of cruelty in the relationship.
It has taken me a long, long time to recover from it. A large part of what was difficult was making myself vulnerable to this ostensibly impartial person and having her treat me so badly while validating my partner’s every breath. Even when it finally came to light that my partner had been having an affair and gaslighting me when I asked what was going on (“IDK FJ maybe YOU want to open up the relationship so you’re accusing ME of having an affair?”) the therapist’s first response was to remark how much it must have weighed on her to keep a secret like that.
It was such profound, profound mind****ery. And I suspect it happens a lot. It’s a kind of abuse for which we don’t really have a term yet.