I am very tired this evening but will try to add something that may make some sense. Right now your H needs you to be the pre DB'ing you so that he can justify what he is doing . If the A does come out in the open you are going to get the " Its over " , " I dont love you " bla bla bla . There is not much you can do that will prevent this. Just remember believe none of what they say and half of what they do. One week after pouring her heart out to me with sorrow and " it rips my heart out when I see how I hurt you" ( W's words) W was shouting "its over " and throwing things at me . A off / A on .
Worrying about this stuff or trying to work out what is going on is therefore hopeless. The way your H reacts to you is often driven by factors that you have no idea about.
Stick with basic DB'ing for now. Validating , avoiding R talk etc , you know the drill. Other than that there is not a lot to be gained by puting any effort in to your H. Turn that energy in towards you and the boys , Leave H to work through his own mess.
I have even more thoughts but the Boys want food . Back later