Being the leader, mentor, or teacher in this department kind of makes me nervous.
I'm not a frequent poster on Bluelight, because so many on here have so much more experience and wisdom than me! And in fact, you in particular have lots more experience with LSD than I do. But this sentence in your post made me want to issue a note of caution here.
If being a mentor / teacher in this setting makes you nervous, you shouldn't feel it is your job to do it. There are many people who enjoy introducing people to psychedelics, and there are even people who have experience with psychedelics and therapy (I say that because you mentioned a "personal block" that your partner is hoping to overcome). I'm not one of those people, and it doesn't sound like you are either. Although I do a lot of teaching and mentoring in my professional life, I think of psychedelics as a very personal internal experience. I wouldn't want to guide someone else at this point in my journey - but I am very grateful to the person who guided me!
You mentioned so many things that concern you, from the art on the walls to the music, the lighting, and the spiritual focus. These are important features of the experience for you, and that's wonderful. I also understand where your partner is coming from, feeling uncomfortable with overt religious iconography and what probably seems too stereotypically "hippy" for his tastes. So you have different preferences, and maybe these differences should be respected instead of one or both of you forcing yourself to match the other's preferences.
It seems like the ideal scenario would be to find someone else who could be a first-time guide for your partner. You could go along for the ride, at a low dose, or you could just let him have a full and personal experience with a mentor. Then, once he's had a session or two to figure out what to expect, you can begin journeying together.