Sounds like he is realizing he has some bad patterns and is trying to stop them. That’s huge. If you set a boundary for yourself-“not one more fight that bad”, you need to tell him that because its only fair and gives him a chance to work with you on new ways of solving disagreements before things escalate. I would recommend working with him to make a list of ways to do this so you can refer to it when feelings start to rise. Maybe define the main disagreement, then take a walk to clear your heads. Is there a possible compromise, etc My therapist just gave me some rules for communicating that are supposed to prevent things lapsing into a fight. You’ve probably heard them. Things like saying “I understand what your saying...”. You could google this way of communicating.
You dont have to co-mingle your money. Sounds like you had better have separate accounts. In fact, that might take some of the stress down a notch.