Does your son have a diagnosis like autism or ADHD? If not, he may be sensitive to all the animus in your marriage. I totally agree that marital therapy, medication, and talking it out won't work. You need to get out before you lose your mind. Do you have anybody to support you through this? It will be hard but you'll be happier. You still might see your pdoc since you're experiencing depression. This may help you through. If you have a good therapist you might see them too for support. I wish you the best of luck.