Could be he is grasping any "fault" (real or inflated) to sooth his guilt. Or maybe it's something else. Either way you should not be berated for such things. I don't really understand why you can't talk about his A outside of the MC sessions. I would think open and honest communication is absolutely necessary to understand how all this came to be.
My W was similar in not wanting talk about it. I just told her "I will be talking and asking questions until I am ready to move on. The length of time is what it takes for ME to get straight. You will just have to suck it up." And so far she has.
Me:49 W:45 M:19 T:22 EA confirmed and ended 8/2014 S:19,17 D:9,5