I'm sorry to hear what you are going through and hopefully things will get better. He is probably just acting out to all the changes he is going through. My only suggestion is to let him sit in the wet or dirty pull-up, if you change him right away, then there is nothing to bother him about that. He has his cake and eating it, too, if you know what I mean. If he has to experience the dirtiness, maybe it will make him want to stop.
