Well who cares if he says you are crazy to some therapist. No one cares. You can get up and walk out

Sometimes people go to therapy to improve relationships and sometimes to end it. If he acts insane in therapy and blames you, then it’s more prove for you that it isn’t good. And you don’t need to do more than one appt. If he acts decent then there is no harm to continue

You can also tell him that you changed your mind about therapy. If you think it will do you no good, then don’t go and tell him you’ve read how it’s detrimental and you’ll think of something else. Like a self help book for couples. Or a website with helpful advice you could read together

To all honesty he might not even raise his voice about anything since you aren’t really addressing any issues with him to avoid fights. So if you lay low and don’t make waves, he might be quiet. In addition if he gets high every night and it mellows him out, he might not cause fights (if you don’t). I don’t know if it’s a positive outcome and if that’s good enough but if the goal is for him not to yell, he isn’t yelling now. I think there are other issues there that are harder to fix than him yelling. Abusers usually rage when they are questioned. If they aren’t questioned they feel in control and have no need to yell