Why? That is a tough question! I don't believe that God chose for my W to have an A and devestate our family, my W made that choice, not God. My W hurt our children,it was not God. What I have learned is that God will walk beside me through the hurt, He will comfort me and revive me as long as I allow Him to do so. I sometimes think that if God isn't fixing this (not that He has to) then it is because something better waits down the road. That something may be, in time, a reconciliation between W and myself in a stronger more committed bond or it may mean a R elsewhere. I am not God so I don't know for sure. I also don't know your whole story but I do understand the "why" question, it's one all believers struggle with in times such as these.
No, God's plan is to NOT hurt the kids. Divorce hurts kids, living miserably hurts kids. THe kids are the victims in all of this.
God gave us free will, and we don't always make the right choices. God can't "fix things", we have to "fix things". What blows my mind always is the fact that GOd already knows what we will choose.....isn't that hard to fathom?