From someone who was in the same place as you this time last year. Your W doesn't give a damn about your feelings. No amount of begging, pleading or applying logic to the situation is going to change that. Forget being cordial or kissing her butt in an attempt no to upset her. Because she still won't care. You need to solely focus on yourself and your child. Consider W a loss and prepare yourself mentally to move on.
Your W had an A and probably hasn't even really offered an apology for it. But is walking around like her stuff doesn't stink. You want to feel better, then let her see you getting ready to move on.
