I have a hard time with the “it’s God’s Will” thing too. This is the way I’ve (sort of) made sense of it for myself:
God wills us to always choose right. If we were to always do his will, then a certain course of events would happen that would eventually lead us to Heaven with Him - a very straight path. However, since we have free will, the first time we choose to sin, God has a “plan B” available. In other words, after having made a bad choice (or being a victim of someone elses bad choice), there is still a way for us to follow God’s Will from that point on and end up where he wants us. Seeing as we humans are constantly making bad choices and sinning, there is a “plan C” and a “plan D” etc… The point being that there is a way from every bad situation to still have good come of it. No matter how many times a person deviates from God’s Will, there is always still a way to return to God, to have there be a good end. Our path may be very very crooked, but it can still go in the direction of Heaven, because God is constantly giving us another way to turn in the right direction.
So for me, it is difficult to say “This is God’s Will”, because I’m sure he had a much better original way. But I also think that because God knows what we will do ahead of time, he already knows what path our life will take - he knows all of the deviations from his path, and all of the ways that we can get back in the right direction. And since that is reality, rather than the original straight path that God must prefer, that is THE PLAN. Theologically speaking, this idea of mine probably has some holes. But it is how I am able to see God’s hand in my life and the lives of others even when some of our actions are very obviously not according to His Will.
So for your situation, maybe it is not so much to think that God wants your dh to leave. But if it were to happen, God has a “plan B” for your family - a way for you to reach Heaven, even if the path becomes more crooked before you get there. It’s a matter of you doing your best to recognize His will for you in each new situation presented, and following it as best you can. The thing is though, each person has their own path, their own responsibility for following God’s Will. So if your dh repeatedly chooses to NOT follow God’s will, that doesn’t mean that you can’t get closer and closer to God even though dh’s bad choices will affect you.