I'm really sorry about your dog meadow. And yes, it must have been very sad, difficult, and very traumatic to witness the seizure, the damage to your dog afterwards, and to have to be the one to take him to the vet to be put down
I had 3 cats & one passed away in my home this last summer, and in hindsight I'd realized that it made a big difference that I was not here alone when it happened.
You are
so right. It is a wonderful exercise for you see how sick your X's response was, compared to someone who is not ill with a personality disorder like him. He was trying to demean you because of whatever lacking feeling was boiling up within him, and his response was ureasonable,
inaccurate, twisted, cruel, and not "normal" whatsoever. Like so many N's behavior's it was also completely lacking in any empathy. Just ice cold anger.
It took a lot of years of the same abusive enviroment to ingrain a certain way of thinking & feeling so strongly within you. It will take time to wind your way out of it (some old feelings can seem to just pop up automatically at first), but in your new environment away from him, I believe you will slowly start to see things differently, just like you already have begun to.
I know at least some contact is necessary because of the kids, but the closest thing to zero contact with him, the better for you.
Take good care...
BT