gosh DK - your situation seems to sound so much like what I went thru with my H at the begining. If you can find some of my old threads you would see what I mean. I think your alot smarter then I was in that I stayed in denial alot - I knew but didnt want to accept and H played alot of games knowing that.
I think it's wise for you to let him contact you for a while and to remain civil. Your S does not need to see or feel the tension that's there, he will thrive so much better for it. But it's alot easier said then done, I know. Trust me I know it sounds strange, but the less you have to do with them the more they try to keep you in their lives.
My best advice......belive nothing you hear, 1/2 of what you see, their actions say much more then their words ever will. Look for consistantcy in his changes, and be careful of the ones that only last as long as the moment. And dont settle for anything less the you deserve.
