I feel so unheard and disregarded. If I tell him how I feel, he won't listen.
Have you been reading DR? It isnt only intended for someone that is left behind, but also for people like you considering divorce.
My basic advice is that by now, you and him have your patterns. He does X which results in you doing Y and then him doing Z and so on.And eventually things calm down until he does X again at which time it all restarts.
My feeling is that you need to start doing Q when he does X. Or R. Or S. Experiment with responses in a different fashion and see how he responds to them.
The key thing to remember is that HE is not going to be the one to change first. YOU have to be the one to change. You need to figure out how to push "positive response triggers" rather than the negative ones that you push now.
I feel like leaving is kind of the last option. It doesnt sound like it will be 'easier' with him gone and divorce brings its own set of challenges. Take some time and experiment. It wont be like this forever.