I have a friend in this situation. Her XAH makes $0 on paper, but works under the table and literally flies in on a helicopter to take the kids out of school and take them to lunch. Nice eh? Yet he has not paid a single dime towards any expense of theirs, nor a dime in child support.
While it took a while to see it, both of her daughters did see it when they hit high school, about junior year I would say. I just want to send you a hug and let you know that you are a great, strong mom. You are the safe one. Your sons may be taking things out because they know you are safe, will be there for them. Their father has only shown them unsteady behaviors, so they don't have that same comfort level.
You can do this. Vent here, we totally get it.