Dear @Flint,
Welcome back to the Wefugees Community and thank you for your question (which you haven't asked before, if I see it correctly).
Yes, as far as I know, your spouse is usually supposed to join you to the appointment (as I also read here, for instance). I am not sure how the immigration office (Ausländerbehörde) reacts if you apply by yourself. However, even if you have to get divorced (in the worst case), you may apply for an independent residence permit (i.e. according to §31 German Residence Act) first and afterwards for a permanent one (Niederlassungserlaubnis). I am not sure if a lawyer can help much for the time being. However, I can recommend to contact a migration counselling office (Migrationsberatung) or maybe even a couple/family counselling to try to solve your issues.
Do you agree with my explanations and is there anything you can add dear @mbeon-fardeen?
In any case, please don't hesitate to get back to us with any further questions.
All the best,
Meike