You're paying child support, so you should know much about how the process works. As a father, it's important that you know what you may have to pay for support or if it's due to you. It all depends on the circumstances of your child custody arrangement.
If you're paying support, one thing to ask is how long the support is supposed to last. For most children, support continues until your child is not a minor any longer. You may also stop paying in some instances, such as when your child is on active duty with the military, if your minor child is emancipated or if your parental rights are terminated.
Custody does affect child support. Both parents have a responsibility to care for their children. If both parents have a child around 50 percent of the time, then the court may not see a reason for child support. If one sees a child only 30 percent of the time compared to 70 for the other parent, the support makes sense for the parent who cares for the child most often. If you have joint custody, it's possible to have to pay, but it's based on a percentage of what each parent contributes to a joint income and how often each person has physical custody.
Child support may also be eliminated if a stepparent adopts the child in place of the noncustodial parent. Once the parental rights of a father or mother are terminated, then they no longer have a requirement to pay support. They may out of respect or a sense of obligation, but it wouldn't be required by the courts.