wow, 32 years of being lied to, that will really mess with your mind imo.
Your H needs to understand this.
I have been causing a lot of emotional pain to him.
Um, he has caused you a lot of emotional pain as well. Your reaction/response is a consequence of his choices to a degree.
As far as the name calling, etc. you do have a choice in that, you can express your pain in a respectful manner if you choose, you do have that power.
You need to bring up the A, as many times as you need until you don't. That is just how it is to process trama, but the manner in which you bring it up is in your control.
He told me he feels like he is living on the edge of a cliff and is continually worried that he might say the wrong thing and I will leave
Again, just a logical consequence that he has to deal with, not you. You have to deal with your feelings and your choices in processing, but this is on him, and YES you may choose to leave him eventually, with or without infidelity, it can happen. This is an opportunity for him to grow through his fear, to rise above it and become a better person for himself first of all which will then in turn benefit you as well should you choose to stay in the M imo.
I too found out years later and know difficulties this causes as most literature is written as if the infidelity just happened and so much time is spent on getting out of the A, NC, etc in the books and not much on how to process this all from a "decades later" perspective.
Out of all the books I read the one that helped me the most was the one previously mentioned "How Can I Forgive You?"
For me the part about having ones pain witnessed and acknowledged was impacting.
Be gentle with yourself, 8 months is not long in the grand scheme of processing this.
Grace