I didn't realize that. Why in the world do you still share finances? Get your own accounts. Close all joint accounts. Cancel all joint credit cards. You are the one caring for the kids so you owe her nothing. If the time comes for divorce, she's the one that will have to be paying child support. I assumed you had separated all that months ago. Get it done ASAP. I did that before my wife even moved out. You've got to protect yourself. You can do that without a divorce. You don't owe her anything despite appearing married.
You cannot be lonely if you like the person you're alone with. Dr. Wayne Dyer