Good luck to you. I appreciate how much you poured out in these posts. You're in a tough spot, but you're not alone. And I'd go so far as to say that we all know what you're going through. I think I know what your husband is going through, too. I think he's probably clinging to the porn and alcohol because, in a strange way for him, he thinks it'll be less painful than shame and humiliation and powerlessness that he believes he will face when he confronts the truth about his past and continued abuse/transgressions/what-ever.
If you want, ask him to read my posts. I think I can identify with him. I can definitely understand the urge to create and foster a double-life, a secret and dirty and shameful life. Because it proves that he's right about himself. It proves that he's a dirty, secretive and shameful person. BUT THAT'S TRUE ONLY SO LONG AS HE DOES IT! If he wants, he can change... and accept himself. You know what? He could still watch porn and be in a relationship! If it's that important to him, why not!?! He'd just have to do it without being secretive from you! Or hurtful to anyone else! I'll bet that if he was honest about what he wanted and how he felt, he might even be able to live chat with people with you (and if that sort of thing is so important to him, with someone else if it's more than you can stand)! But... but... he can't put you and your kids in danger by drinking when he's watching them.... He can't have a secret life whose only purpose is to destroy your life together... because that's the only thing that secret life is good for. And he has to be honest about his wants, needs, feelings and what-not... not every single second but about all the stuff that's important.
Get over yourself. Get your head out of your ass. Your pain is a big deal, sure, but it's not THAT big. Is it really worth wrecking your marriage and your life? And if your life and marriage is that bad, then be a man and either make it better or end it like a man.
CdnDW, I hope I didn't step on your toes too much there.... I apologize if I did. Or if I offended you.