Just need to clarify something. I also think score carding is bad. For years W kept a score card while I was too afraid to keep one for myself. So W wouldn't allow herself to be nice too me until the score card was clear. That usually took tons of groveling
Instead what I'm saying is to throw away the card and force her to throw away her card. Instead of keeping score just follow this simple mantra.
"if you're nice to me, I'm nice to you. If you're mean to me then I am under no obligation to be nice to you."
You don't have to be mean, just ignore her, and avoid her. If she asks why say its because she is being mean. If she escalates it further and says that she'll leave tell her that's fine, that you don't want someone who will be mean to you.
As soon as she is nice again, then you are proportionally nice. It's that simple. You don't hold it against her. If she continues to be mean because she refuses to wipe the offense from the score card then you continue to withhold the niceness.
The difference is that score keeping often turns into grudge keeping. What I advocate is to wipe the slate once she behaves.
Your goal is to slowly start creating a dynamic where your W gets less and less benefit from being mean, and more and more benefits from being nice.
Afterall Navy you have nothing to lose. What's she gonna do divorce you? Oh right she already threatens that. She may not outright say it every time, but she knows she can use it as a nuclear deterrent on you.
Which reminds me of one more thing if she is using the divorce card to win fights, you seriously need to call her bluff.
If she does it again immediately walk away. Refuse to talk to her until she comes down, and pretty much stay away until she either reaches out to you or demands to know why you are shunning her.
Then tell her this:
"you threatening me with a divorce is the worst thing you could do to me, it is quite gut wrenching emotionally, if this keeps going on things will not work out for us, and we'll never find peace. So I need some space to think"
Just be careful you don't say this midfight or you will really be adding fuel to the fire, because she'll probably think you're racing her to the divorce and will seek to beat you for maximum pain on you.
Disclaimer: these types of techniques are not your typical DB if your WAW is in the beginning stages this will just utterly repel them. This applies more in situations like Navy's where the WAW refuses to leave, yet refuses to work on the marriage. Which is a variation of cake eating.