I had almost completed my therapy training before DDay, and would like to contribute my professional insight.
That therapist is playing fast and loose with his boundaries. Pursuing you for an appointment rather than giving you space to make a decision? Saying "If I were a friend I'd use harsher words"? Talking almost the whole session!? Pressuring you to not R?! The further you got in your story, the more shocked I was.
He is likely concerned about you and thinks he's acting in your best interest. He's not. He's reacting from his own fear and discomfort. His job isn't to tell you what to do. He could give his view if he's concerned for your safety and well-being, but a therapist isn't supposed to be another authority figure. Even when therapists have to confront a client, it's with the goal and intention of helping the client to build their own capacity to see reality without trying to deny it, find their values, and help them in building the skills to live a life in line with those values.
I think he made a decision about your WH early on and that's what he sees it through. Whether his decision was accurate or not I can't say. The best thing for you is to develop your ability to consider alternative viewpoint in making your decision without being swayed to act against your judgement or values. You've seen a lot more of WH than therapist has. You have different information.
I also wouldn't rule out attraction. He wouldn't be the first gay man to sleep with a woman.
Honestly, something about him reminds me of my old therapist. She was very critical of my BS. If I tried to talk about my role in conflict, she'd turn it back to my BS is the problem. She kept telling me to leave after I told her repeatedly that I wasn't. Oddly, she loved AP who assaulted me and emotionally abused me for months. I describe love bombing to a T and she said nothing. I would tell her about ways AP offended or disrespected me, she defended him. I don't get it, except she had him in a class she taught. Maybe she liked him as a student and that clouded her judgement, as if abusive people aren't different people to the outside world than to the people they're abusing.
I also wanted to point something out from another person's post while we're talking about therapist red flags.
Another therapist asked me to evaluate if my WH was a narcissist or had any other personality disorder. She said personality disorders do not respond well to therapy, and she would not want to work with my WH and me if he did have a personality disorder. I can respect that professional stance.
This therapist is incompetent and should not be practicing. Your therapist was not skilled enough to deal with your husband, but rather than saying that, the real problem is how irredeemable your husband is.
The idea that personality disorders are untreatable is old and outdated. Personality disorders is a misleading term. It was once thought that someone with a personality disorder had an intrinsically defective character, and the best you could hope for was symptom management, but that's not true. "Personality" disorders are patterns that develop in response to childhood trauma and/or attachment issues as a means of survival. It's becoming more apparent in the field that what we call personality disorders are really different manifestations of CPSTD. It's likely that when the next DSM comes out, personality disorders will be removed or become a subcategory (not the right term but brain has not slept in three nights so) of PTSD.
Not to mention, HER, the professional trained in diagnosing, wanted YOU to evaluate if your husband had NPD? That's laughable. That's not a comment on your lack of intelligence but lack of skill set. Diagnosing is hella complex. Therapists have to give a diagnosis after one session. This is purely for billing purposes and not the best practice, but we have to do it to get paid by insurance companies. Blame lobbying. For this reason, if you don't have a diagnosis beforehand, a therapist will usually give a "little" easily changeable diagnosis (depending on the state, you may have to go to court to change certain diagnoses because of biases) like "adjustment disorder" or "grief disorder". You might have a "working diagnosis" which is a way to say you suspect a "bigger" diagnosis like Major Depressive Disorder or General Anxiety Disorder. I'd be skeptical of anyone who added a personality disorder as even a working diagnosis after one session about if the clinician isn't operating from some bias or their own history. The only "big" diagnosis I'd diagnosis after a single session is PTSD, and only if the client says specifically, "this traumatic thing happened and I'm experiencing the symptoms of trauma." Ok, clients don't say it like that but you get the picture. And even with PTSD, people can surprise you. I've had many, many clients come in and say, "I have all this stuff and all these belief patterns and I don't get what's wrong with me." Then a few sessions in they're like, "well I did have all these things happen to me in childhood and this traumatic thing happened a bit ago, do you think that that could have anything to do with how badly I feel?"
This is all to say, a lay person is highly unqualified to armchair diagnosis their spouse. You can't distinguish between NPD, BPD, bipolar, MDD, GAD, and PTSD, which all have overlapping symptoms and tend to be misdiagnosed for the other. Usually it's PTSD being misdiagnosed as something else because the client isn't aware that the things they went through were trauma and the therapist made a judgement without asking the right questions. Interestingly, if you had presented to therapy with the same symptoms as your husband, she would have probably said you have BPD (borderline personality disorder). BPD and NPD both have a LOT of overlap, and in the field the distinction usually comes down to gender. We interpret the same symptoms in different ways based on if the person is a man or a woman.
I have strong opinions about therapists and ethics. I'm going to step off my soapbox now though.