Not kicking C4TB while she is down, but because you guys keep repeating things (Correct me if I am wrong):
-They were married less than 5 years ago
-They did not kiss or have sex prior to marriage and are part of a serious religious community that enforces this
-The AP is also part of the community as far as I can tell
-She had at least 1 pregnancy scare with AP while engaged - BH had to discover and catalyst for all of this
-She says she married him for the religious appeasement and did not love him until she got pregnant (she says he taught her how to love)
-She knows she screwed up and is finally starting to see how controlling and selfish she is in this marriage (Give her some breathing room on this)
-The not remembering thing is still questionable and even she is starting to question that
-She told her BH to go see the AP and clear things up (This was a step in the right direction)
-AP confirmed some more and a new AP came to light who no one has details on
-The first AP was married and still is. The OBS knows and is messing up AP's life
So, now to the real thing she needs right now. He is asking for a poly I think. (She mentioned this)
C4TB - What do you think will happen if you fail? Secondly, what are you doing to help your BH with the trust issues he is going to eventually come to? (You were and are still doing GNO, I have my opinion, but you know what you should do. Small sacrifice IMO.) I know you were talking about the bank being close to the restaurant and missing times to check in. How are you working on shoring those kinds of things up?
He is going to start to question anytime he didn't have eyes on you. Think about how much you are questioning your memory. He is going to question that by 1,000.
You have been resistant to do your own detective work on your activity. Do you think making that effort might help him? I think it might show him a change in your behavior to actively head off this trigger as well.
Like when you heard your BH heard about the after marriage part and you knew he needed space, so you took the kids and gave him it. (Great response) Kind of foresee his reaction and come up with a way to fix this. Also be worried, one of your friends might know about other extra-marital events. You might want to ask a few of the closest and disclose your issues with your memory. They might be able to help.
Just trying to help to prepare for the next round of nut punches coming to your BH.
Keep improving. It is all you can do now. He is going to get back into limbo. That is going to be rough on you again.
These pre-emptive moves might help.