I should add that she has the stomach issue about once every few months and usually it's external stress and not me
To answer your question about what on particular looks like you being an abused person justifying her abuse of you, I've just selected a few quotes from the section in your post where you are responding to me
This example above ^^. This is you highlighting she has a legitimate health issue. But, a health issue is something for a medical person to help her with and she needs to seek out. This issue is being used as justification for her behaviour. It isn't one. You accepting that it is is you being manipulated and groomed into her lies to keep you feeling compassion for her. "If only you behaved better she wouldn't be in pain and have this issue." Is the message and lie. When actually "if she sought medical help and changed her lifestyle or emotional responses then her stress levels would reduce and she wouldn't be in pain" is way more likely to be the truth.
also don't just "disagree" and often I'm manipulating like I said above to try and downplay some mistake I made
This again is another example. When someone is scared of another person and treading on egg shells, being totally honest is going to be met with abuse. So you might say a version of the truth to try and defuse the situation. That is then met with abuse and further manipulation. And this becomes a cycle.
You aren't manipulating here. You're being abused and trying to adapt behaviour to reduce abuse. Although you don't see it as you believe her lies. It's always your fault right? You behaving in wrong ways that upset her that's the abused mindset.
(procrastinating on filing taxes until last day,
This is ok. This is normal! We all do this. Why would this be a bad thing? You got it done. And it's your responsibility. She's using every day things to blame you.
not remembering her cleanliness protocols e
Again, this is ok. We all clean differently. If something like a cleaning ritual sends her off then she needs to address that. It's her trigger to manage. Not for you to adapt behaviour.
rather than full on apologizing and not making any excuses
You don't have anything to apologise for really in the examples you have given. She is using elements of truth, twisting them and making them way bigger, to manipulate and abuse you. These are classic abusive behaviours.
That's what is triggering to her and causes her to lose it
Again, her triggers are for her. If she loses it , it is for her to work on that. Not for you to adapt your behaviour so that she doesn't lose it. Because no doubt the goal posts change all the time. You adapt in way A and then she springs up way B needs doing. And then way C. And then a version of way A. So that you can never win. Never do it right. And the abuse continues.
as when we were working through my betrayal and the things I did behind her back I kept arguing and downplaying and it became a huge trauma point for her.
You didn't actually betray her. This has been used as the justification for her behaviour. And has been blown up into something massive when it wasn't.
A sign of a very unhealthy relationship is one where the same issue is argued about over and over and over again. A healthy relationship there is an argument , both sides hear each other, apologies made, each is understood and it is over. Never to be argued about again as the issued is resolved.
I say the above by being in a healthy relationship for 20 years. And having been in a coercively controlling one for 5 years before that. The controlling behaviour is always in an element of truth which is why it works so well to manipulate reality. And your compassion for their wellbeing is manipulated and abused. The mix of those things make you adapt your behaviour, and try and behave in a way that keeps them ok by abandoning yourself. And the deeper and longer it goes on for , the more normal it gets and the abuse gets worse bit by bit, but that's hard to see when you are in it.