Hello and welcome to HW. Lyn has given you excellent advice and she is a very wise Lady. From reading your post I sense much animosity toward your wife. Whatever is going on is her fault. I am sure you have thought of counseling for both of you. It does sound like you are so upset with her that your wanting out and perhaps that would be wise.
IMHO parents must put the desire to protect their children above their own needs. I sense that your son is in the middle of whatever is going on between you and his Mother. Your son is living in the drama of your everyday unhappiness. Sometimes in a relationship one person has to let go and move on. Children internalize as anxiety the on-going feuding of the parents. Your son is not in a safe place right now emotionally. You need to put his needs into the big picture.
Just my 2 cents worth. I wish you the best and hope you can find peace for you and for your son as well as for your wife.