What has he done to change, improve or even acknowledge his part in all of this? Was it more than a passing conversation?
Mr. A wanted a divorce and now it sounds like he had NO idea what that would entail. It's time for Mr. A to do some work on him as an individual and face the reality of what a divorce means.
I know a couple that have been legally separated (not much different than a divorce in this state) for 14 years. It's a very, very sad situation. They spend TONS of time together, are sexually active with one another yet no work has been done and they are now in a decade+ loop that neither can break free from. No work has been done, no commitment has been made and a good portion of their life is still the same.
What is Mr. A doing different? What is he doing about Mr. A?