Friend
I read your older posts...
You don’t have to like separation. It’s like a bitter, foul-smelling medical potion that really doesn’t taste great and might initially make you all queasy and leave a bad taste in your mouth. But... it cures whatever is ailing you.
I noticed some key-points: You had a previous marriage/relationship with domestic violence. He has had a porn addiction for years (seemingly most of the marriage). He is viewing porn focused on teens – like your daughter(!!!!). He has been mentally abusive. He has been physically abusive.
You need this separation. You need the distance. You probably need the divorce too.
I have some (basic) past experience in dealing with domestic abuse. It’s been several decades, but I don’t think behaviors change that much, so I think it still applies.
People from abusive relationships (be it from family of origin or partners) tend to seek out abusive partners. I guess it’s connected to a level of self-blame, and you are always trying to make amends – to "heal" someone. At your cost. In the strongest of words I encourage you to get some professional help for YOU. Like therapy, individual counseling, group-support via abuse victims groups... Heal yourself – something you can’t fully do while in an abusive relationship.
There is a realistic risk that his abuse progresses to sexual abuse within the family... Yes... your teenage daughter. It might not be a high risk – but are you willing to take that risk? For your daughters sake a separation – a sip of that vile tonic – is necessary.
Can he change? Well... research at that time (over 20 years ago...) did show that with intense therapy abusive men could change. But... the odds of a relapse were greater if they continued within the former abusive relationship. In other words: If he were to acknowledge his issues, seek help and do intensive therapy he could become a safe partner for someone else. You two already have a pattern, a form. Chances are you two will slip back into that pattern, where his resentment grows and eventually snaps.
So yes. I trully get the pain. I get the aversion to what you are facing. But the realization that this is your path to your brighter future could fuel you on.
Finally – Please get help. Call a domestic abuse hotline and see what resources they can offer. I am willing to put money on that you can join a group of women in comparable shoes that are helping each other with recovery.
"If, therefore, any be unhappy, let him remember that he is unhappy by reason of himself alone." Epictetus