Should I only spen the child support for one child on that child?

You could try to pool your child support and try to spend it as equally as possible on each child. That way neither child feels left out or loses. Both fathers should be willing to help out and take their kids. It is called parenting and they really should do it for the kids' sakes as well as their own. It also gives you a much needed break. It is not easy to raise children. Any help you can get can go a long way to making life better for them, their fathers, and you. Good luck!