I want to start off by saying I am sorry and have nothing but compassion for what you are going through right now.
Before you ask him one more time if he is sure that this is what he wants to do you should consider that your husband has had multiple EAs and is in one now. You speak about overlooking these incidents as a good thing when in essence it lowers your value in his eyes.
Relationship and attraction are about value. People who jump through hoops for you are not valuable, and are therefore not attractive. You value people who are confident and self-sufficient, and that you feel you need to work to get. When you get attention from those people you feel good about yourself.
That's why GAL, act as if, and heading the other way work. You're establishing yourself as a person of value who is not going to jump through these hoops or tolerate this crap.
Double down your efforts to lead a life that anyone would want to be part of and you don't care if he's done or not.
That's the attitude you need to assume, and if its not authentic act as if until its real.
Your view on this needs to be "go do your thing, H, do what you need to do in order to find happiness. I'm going to live an amazing life. If you want to be part of it in the future, we'll have to talk about that, but for now I wish you well"
You shouldn't say that to him directly, but everything about the way you react to her and respond to him should say that for you.
Don't be rude, don't be dismissive, don't be passive aggressive or antagonistic, just be uninvested.
