People have said so many wise things here, Liz, and I echo their support, compassion, and caring for you.
One thing strikes me from your post. Because your husband works from home, and you home school your son, most of your time is spent in a closely locked circle with just the three of you as major players. I know you and your son travel for tennis tournaments, and he has outside activities, and your husband travels for work also. But the bedrock living is done just with the three of you.
It is insular, and I think it helps keep you locked in this circle. My therapist once said, talking on my dysfunctional childhood family who I tried to escape, that living in a dysfunctional family is like living within rubber walls. Everytime you try to exit, they bounce right back in. The whole family system exists in a dysfunctional stasis, and it NEEDS that structure, and it has a life of its own.
This is part of what you are fighting, and I found it despairing. Maybe try to bring in as many new influences as you can, and get yourself out in the world and opened to other people, ideas, ways of being, as you possibly can.
This way of living is like living with carbon monoxide unknown to you permeating your house. You don't see it happening, but eventually it will kill you.
ShootingStar1