Remarriage is usually not a reason for a change in custody unless other factors are involved. Parents naturally move on to new partners after a breakup. The fact that they have a child doesn’t change this. Unless the new relationship affects the child or his relationship with his other parent, courts are not likely to modify custody because of it. Judges are obligated to place custody based on the best interest of the child.
A child’s best interest isn't served when his parent’s new spouse is abusive toward him. In this case, a judge might be inclined to move custody to the other parent. For example, if the new spouse shows excessive favoritism to his own child, criticizing and harshly punishing his stepchild, a court might consider this harmful to the child. However, the parent requesting a change in custody has the burden of proof in court. The abuse must be substantiated. One way to accomplish this is to petition the court for a custody evaluation. In the process of the evaluation, a child's pain and confusion over the treatment he’s receiving becomes part of the court record.
Sometimes, remarriage improves a situation that caused the court to deny one parent custody in the first place. In the 1988 case of Sealy vs. Sealy, a court in South Carolina indicated that a parent's remarriage improved his chances of receiving custody. The parent seeking the change of custody still has the burden of proof to convince a judge that his remarriage warrants a modification. However, the proof can be based on external factors, such as improved finances, an upgraded home that was previously unsatisfactory, or another nurturing adult in the household if a parent was previously denied custody because he works a graveyard shift and is not available to his children overnight.
One of the greatest impacts on custody occurs when a parent wants to relocate because of her new marriage. In most states, courts base such decisions on the children’s relationship with their other parent. If it is very close and the other parent sees his children often, courts are less likely to allow a parent to move her children out of state away from him. An exception sometimes exists if the move will result in significant additional income into the household. This would improve the child’s home life and would be in his best interest. When a remarried parent with custody wants to move simply because her new spouse lives in another state, a court might change custody to the parent remaining behind, especially if it means not uprooting an older child from his existing school system, extracurricular activities and social network.
Technically, the courts in most states will not include a new spouse’s income in child support calculations. However, when a parent’s remarriage affects the custody arrangement, this can affect child support. The more scheduled time a non-custodial parent has with his children, the less his child support obligation will be. When custody is modified because of remarriage, the child support order in place usually changes as well.