Did you really not expect her to over-react? I don't even know her and it didn't surprise me.
You are correct, she threw a tantrum b/c she didn't get her way. She controls you. You realize that, don't you? She will not give up that control easily. You should have stood up to her the first year of M. But, that's in the past and now your family experiences the consequences. Be careful and think it over before you act.
You made what you believed were the right choices for you and your children. She has the choice of staying or leaving.
Make sure you have thought this through very carefully. If she leaves without the kids, who will take care of them while you work, etc.
Don't discuss the porn and other things right now. It will not save the M by discussing it or making promises. Don't apologize for it any more. Don't apologize for anything you've already apologized about. It doesn't help to keep doing that, and it makes you appear weak.
Stay focused on one thing.....moving or not moving. Don't take all the problems of the M and hash over it again.
After she threw her fit and you are seeing the pain your children are in.....you regret telling her you aren't moving. Do not do anything just b/c this board tells you. This is your life! You have to do what's right for you and the kids.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!