Pennsylvania uses the "income shares" model when calculating child support. The formula begins with the combined net income of both parents and the amount of that total they could be expected to spend on the children’s needs if they had remained together. The parent with the higher income contributes a proportionately larger share. If you are the parent with custody, you pay your share directly, for food, clothing and shelter. If you are the non-custodial parent, Pennsylvania expects you to make a cash contribution to the other parent toward your children’s care.
When a custodial parent marries, her new spouse usually contributes income to her household, where the children reside. Presumably, her spouse is paying toward the mortgage or rent and utilities, which represents a portion of the children’s needs. This can result in the non-custodial parent paying a less. The court can consider this when calculating child support, according to PaDivorceOnline.
Since the children are not living with the non-custodial parent, if he marries, it generally has no impact on child support calculations. His new spouse isn’t contributing to the children’s shelter needs because they don't live with him. His income and his share of the children’s overall support remains unchanged. But this is a general rule and a judge can make some exceptions.
Pennsylvania judges might consider the income of a non-custodial parent’s new spouse if the parent is trying to avoid paying child support. For instance, if she is voluntarily unemployed or underemployed, the courts might use her spouse’s income in child support calculations in lieu of her own. If she claims that her own expenses are so great that she has nothing left over for child support, the court will usually count her new spouse’s income as a source available to her for payment of her debts.
If you are the non-custodial parent and you have married, and if the two of you have any jointly owned assets that are producing income, half of that income can be attributable to you. If it raises your monthly income significantly, your share of your children’s support may rise.