First of all, a big giant guardian angel hug to you and your children. I am so sorry that you must continue to suffer in so many different ways.
Here are some of my random thoughts which may or may not be helpful...
Have you tried EMDR (not sure if that is the right acronym)? To try to erase what you have seen, get some of those images out of your head. I don't even know if that is what EMDR does, but I'm sure you know more about it than I do.
In the early days of discovery, I watched the porn website that my SAWH said he watched to get a feel for what he could be watching. I will never get some of those images out of my head and it was "just" vanilla things like anal sex, etc. I can't imagine what you've seen and how those images must torture you.
Do you have a dream interpretation book? If not, can you get one from the library? I know it is obvious what your dream was about, but there may be some details that may give you insight as to what may be triggering this and it might help you put some of those dreams to rest.
You are doing everything humanly possible (within our broken system) to protect those children and you are doing great.
Know that there are many out here that are praying for you and your children. Good karma MUST come your way from all that you have endured.