You seriously need to listen to Sandi. You have been tolerating this behavior and the outcome isn't getting any better. It has actually gotten worse. So its time to change the plan a bit. Your W has no problem laughing and joking with you as long as she benefits in some way. Your W needs to experience some sort of loss and maybe even some shame. Trust me you can not nice your way into making your MR work. My question for you is great about your W that your holding on to?
