Slow down, friend. Let me talk some Army-ese here. Breathe. Get a good sight picture. Squeeeeeeeeeeeeeze the trigger - don't yank it, or your shot will miss its target. Engage the nearest target first - that's the one that can kill you.
IOW - don't be in a hurry to get worried about "YEARS of this." Think your next move through - act, don't react. Get a good picture in your mind of what you're aiming for now - not years from now. There are people in your corner. Force yourself to focus on today's challenges and tomorrow's - not the hypothetical challenges of year 2020.
It definitely sounds like Monsoor has checked out of the Hotel Reality. I would suggest that in many ways it might be worth considering the possibility that this is completely independent of what has happened in your marriage. It sounds as if this was always some kind of latent possibility - some people are, I think, sort of pre-wired for this type of "vision," and Hwood is particularly good at activating it. Your M could have been solid as a rock, and you might very well still be seeing this. Could a stone solid M have absorbed and accommodated such weirdness? Maybe, maybe not. But the bottom line is to recognize that this is a Shmedlap Thang and clearly not an Aliveandkicking Thing.
Your mission, should you choose to accept it, is to make decisions for now and tomorrow's now, for you and the children, and let the years take care of themselves. The years are a problem, but they're not your problem.