I'm not back here very often, but came across this thread while updating my own. To even have to wonder whether those in crisis know what they are doing is totally incomprehensible to me. Think about the words Bomb Drop.... something completely out of the blue, unknown and unexpected at the time of delivery.... at least to the recipient. Now, think of the Bomber and just how long this event was planned and thought about beforehand. Irrational thinking doesn't render a person incapacitated. It just gives them more leeway towards making stupid choices.
I really believe, like Stayed, it all started innocently enough, with each tryst becoming more exciting and enticing, until finally they get caught too deep in the quicksand to escape. That's when the real panic of being found out ramps up series after series of rash choices that ultimately build to the bomb drop of epic proportions.
After they choose to leave (and almost always run to the AP who's been there all along) that is when it should all become about the LBS taking back their power. You cannot both play the victim and expect any of the dynamic to change. Someone has to be the voice of reason and move out of that toxic space, and it sure ain't gonna be the MLC'er because they lack the strength and clarity. And, if the LBS doesn't learn to drop that rope, they run the dire risk of staying in a state of cycling and monkey braining that prevents them, too, from ascertaining any sort of bearings or clarity. That's is a huge reason why we are all told to "put on our own oxygen mask" first. As difficult as it is in the aftermath of BD, the best chance the LBS has is to take the emotion out of all dealings and use a business approach, especially if a D is filed very early on. It hurts, it sucks, it isn't fair, but it is life. It doesn't have to make sense to us because it isn't OUR decision, it is our response to their choice. What is chaos to the fly, is perfectly normal to the spider.
So, it really does no good to assess blame either way. It is what it is, and nothing will change it. The best we can do is live our remaining days learning, growing, and continuing to be our best possible selves. Life after this will only be as good as the LBS chooses to make it. The MLC'er may have dealt the cards, but that doesn't mean that the LBS can't play those cards and drop all aces.