"it must've been very difficult to grow up around that. I know she was physically abusive to him. My mum is always saying that I need to understand he didn't have a 'normal' childhood etc."
OK, so hard facts here. If he grew up in this kind of environment, he will have been damaged by it. It might impair HIS ability to be a 'normal/adequate' parent himself.
You don't need to be told off by this man, for any reason. HE was ungrateful, and rude.
Don't cook him a breakfast for a good while to come. Let HIM sort himself out.
One point I ought to make at this stage is that his mother was, for reasons of schizophrenia, abusive to him. That's what he thinks a parent is. You getting PG may be triggering him to behave like that parent. This could be the start of a very dark period. Abuse often starts in pregnancy.
Fact is, you need to make sure everyone understands that YOU have a choice, to be treated with respect by everyone, or you can walk away.
Your mother's words bother me intensely, as if she is saying that you have to put up with his mother for the sake of your relationship. That YOU are not entitled to be upset, and that you have to lump it. Why does she think that? Is/Was her marriage abusive/dysfunctional? You don't have to put up with ANYTHING. Life doesn't have to be hard, relationships shouldn't be so strained.
Your P needs to understand that HE deals with his mother - not pussy footing around her. Her being schizophrenic isn't YOUR problem. He needs to try to insulate you against her behaviour, not berate you for her episodes.
He needs to tell her that she has to be respectful of you, or that she will be on her own. YOU get put into first place as you are NOT schizophrenic, and when you are aggrieved it is with GOOD reason. If she needs help, medical help, she has to get it, he can support her in that, but tiptoeing around her, feeding her behaviour is not acceptable long term.
FWIW, I'd have binned the relationship after the hoover smashing into the door. Who in their right mind wants THAT as a MIL? or now even worse as a Grandmother for your child.
Your P needs to FULLY understand that as a package, he is flawed, and accusing YOU of anything is a bloody cheek. He has no right to berate you, making you cry and ruining an otherwise happy Sunday is just ridiculous.
This is the time for you to be strong love, with everyone.