@Nikjay,
Are the present wife's children also his children? That might be a consideration, though it sounds kind of unusual for a current wife without a separation agreement to be claiming child support.
Can't tell you if your support could be cut, but if it comes down to garnishment of wages, there is a limit to how much can be garnished.
Don't you have a lawyer that knows these situations? If you don't, you really, really need one.