The tricky part is to fight for that side of my H while letting the other half know he is no longer welcome in my life.

This here is a good goal. Now, specifically tell us, what can you do to validate and promote the side of your H you cherish, and what can you do to set some healthy boundaries in a non-confrontational way?
I think maybe ignoring the pornog. for now may be best. Some times you have to put some things on the shelf for a bit because it is too much to try to change all at once. Pick and choose what you think is priority and work on those.
Also, how can you really change the interactions when H is getting heated? Think through this 180 carefully. This is a good opportunity for you to change the dynamic. Part of what will help you to not lose your cool is to detach. Start looking at this from the outside, not so personal, as if you are watching a character in a movie. Take your time to respond, don't react. This stuff takes practice. If you are feeling reactive, say nothing. You don't have the power over how your H acts, but you do over how you act. You are strong enough to be here and going through this, so I think you are strong enough to change this dynamic. Right now, maybe that is the priority so you and your family isn't living in so much tension.