Hi, using a throwaway account to reply to this - obviously it’s a sensitive topic.
I was in this situation for four years and, like you, I often thought ‘it’s because of his autism’ and downplayed it.
I would be punched, beaten, kicked and bitten on a regular basis, sometimes several times a week and even more so whenever I tried to end the relationship or take some space - so I know how scary that prospect is too!
There were also all manner of insults, put downs, accusations and whatever else that came off (to a neurotypical person) as sheer insanity but later made sense the more research I did into ND (eg. if an insult had been heard somewhere it would be randomly used and repeated - hence sounding out of context in our relationship. God knows where half of it came from!
My things would regularly be broken, either during a meltdown or just to be spiteful.
The meltdowns that led to this violence would happen over seemingly nothing to us, but are a big deal to someone ND (eg. one time a clothing item ‘looked wrong’ so I got my head smashed in).
Whatever’s causing it, it’s still abusive and it’s still scary. Your partner needs to get some help. Mine started to, but lied to the professionals constantly, would never admit the violence - so no improvement. Hopefully yours is better!
It’s been almost a decade since I was able to get out (ended with police involvement and physical removal) and I have PTSD, as well as physical scars where chunks were bitten off me.
I’ve heard through mutual friends that I’m still to this day talked about - how I’m the ‘bad guy’ and an awful, abusive person for putting him through the ‘trauma’ of the police, but I don’t want to hear it and I don’t let it bother me. It was my only choice. I’d be dead without and I know I did the right thing.
Please, please, put yourself first and look at what you need and/or want from this relationship. If it’s staying with him and seeking further help - that’s great as long as it’s helpful for you too.
If you need to leave, that’s also fine. You don’t need to feel bad or guilty, because you need to feel safe too.
If he doesn’t take the steps to prevent this, it will keep happening and it WILL get worse.
Sorry this has been a bit of a ramble, I’m probably not much help but I hope you’re OK, OP.