Until we had DS we never really talked about our respective childhoods with regard to parenting and discipline and the disparity between the parenting styles of our parents was vast. I'd always thought that the awful stuff I and my siblings experienced were of the times, but realising DH had a very different experience - and a really good one, despite having parents of the same era, ethos, religion, and background, it shocked me. My siblings are on a similar journey of enlightenment. Some of us have had therapy and others are strongly considering it. But he's got you, and he seems very willing to learn and understand so that's great.
When I'm triggered I get really furious and cry and start shouting. DH almost never raises his voice. He never likes speaking about difficult things, and if he can he will bury his head in the sand forever.
I've a couple of suggestions from my own experiences. I'm naturally quite emotional and know I can get reactive. But I also know that my initial reaction is often not the best approach. So, when we have a disagreement, often we park it temporarily to consider the issue. And we always park it if we feel ourselves getting angry. We've a no-shouting rule, and have stuck to that for the last 18 years bar once or twice.
I realised some years ago that all my emotions initially present as anger, and by reminding myself of that, I feel out what is the driving emotion - fear? frustration? envy? sadness? taken for granted? and I can then explore why I'm feeling that way and begin to structure what I want to say, and by labelling my emotion it really helps me verbalise it effectively without getting upset.
Our aim in these discussions always is to listen to each other and find a common ground - we may not agree with the other but we respectfully give their views our full attention. Our secondary aim is to find a ground somewhere in the middle that both of us can live with.
When I get stressed, I can veer towards being panicky and tearful. I find that I can successfully diffuse that feeling by cracking a joke about it or a bit of dark humour. That allows me to focus on the issue at hand and it's kind of morphed into into a valued skill that I use in my job as well as in my relationship.
DH had an ex that would go apeshit at the littlest things so he started off burying or ignoring issues with me. However, over time seeing my approach I think he has found it easier to talk about stuff that he used to bury or ignore. So a healthier dynamic grew out of knowing I would not fly off the handle if he wanted to broach something.
We don't always get it perfect but I am pretty proud of how we communicate especially now our DS is older and learning to express his own issues in a healthy way. So maybe that's another focus - you and he need to work on a better communication style so that you can model that to your DD.