I know you're not trying to argue, but unfortunately, this is one of those "chicken-and-the-egg" things:

Do I insist upon the A being over (and 100% no-contact and transparency) before I meet any of his emotional needs?

Or will my not meeting any of his emotional needs make him LESS willing to end his affair and go no-contact?

I am firmly in the first camp, but that's probably NOT what DB teaches.

Puppy