I try to set boundaries as I've read that is important but I am never able to follow through. One major problem is that when I know things are escalating and I try to take a break so we can cam down she refuses to let the conversation end. How can I convince her to let us take a break from an escalating conversation?
Hi Picasso. Welcome. I can really relate to everything you say here. I've been in my relationship around the same amount of time as you, and I am also a very calm and non-confrontational person by nature. I had never experienced the kind of conflict (both frequency and intensity) I have with my current partner.
As for your question above, I have learned the hard way that you cannot "convince" her of this. My wife does the same thing - she always wants to get the last word in and will not let a conflict die. Sometimes the only solution is an enforced break. Go for a short walk. Go do some shopping. Go to the gym. Reassure her that you'll be back and you can discuss things further once things have calmed down. And then just walk out and don't take the bait if she tries to argue about it.
She may get even angrier initially, but over the longer term this will benefit you.