¶1 Defendant’s assignments of error are directed to the trial court’s finding of fact that the defendant is capable of providing child support and to its conclusion that the plaintiff is entitled to an award of $189.99 per month in child support. The initial question presented is whether defendant-mother has any legal duty to provide support for her children. G.S. 59-13.4(b) provides in part:
In the absence of pleading and proof that circumstances of the case otherwise warrant, the father, the mother, or any person, agency, organization or institution standing in loco parentis shall be liable, in that order, for the support of a *330 minor child. Such other circumstances may include, but shall not be limited to, the relative ability of all the above-mentioned parties to provide support or the inability of one or more of them to provide support, and the needs and estate of the child ....
¶2 Under the statute, the duty of the father to provide support is primary. Tidwell v. Booker, 290 N.C. 98, 225 S.E. 2d 816 (1976). However, the mother also may have a duty of contribution upon proof of proper circumstances. See McKaughn v. McKaughn, 29 N.C. App. 702, 225 S.E. 2d 616 (1976). Such circumstances have been shown in the present case. Plaintiff-father had exercised custody and control of the minor children since the parties’ separation and, under the terms of the court’s order of 21 December 1978, will continue to exercise such custody and control. The trial judge found as a fact that plaintiff-father is in need of financial assistance from defendant-mother for the partial support of the children, and that she is capable of providing it. He made specific findings of fact concerning the monthly expenses and average net income of defendant-mother, the average monthly financial needs of the children, and plaintiff-father’s monthly net income. Although there was no finding as to plaintiff-father’s monthly expenses, the court’s finding that he was in need of financial assistance is supported by competent evidence in the record that monthly expenses for himself and the children totalled $1,049.20, which is $224.20 in excess of his average net income. Likewise, there is competent evidence in the record that defendant is regularly employed with a steady income, and that she has a working spouse. The finding of fact of defendant-mother’s ability to pay, as well as of plaintiff-father’s need of such payment, being supported by the evidence, is therefore conclusive. Wyatt v. Wyatt, 32 N.C. App. 162, 231 S.E. 2d 42 (1977). There is no indication in this case, contrary to defendant-mother’s contention, that the trial court intended to shift the primary duty of support to defendant-mother. Having considered “relative ability” of the parties to provide support in view of their expenses and incomes, as required by G.S. 5043.4(b), the trial judge merely determined that plaintiff-father should receive some assistance in bearing the cost of supporting the children in his custody.
¶3 The next question presented is whether the court erred in ordering defendant-mother to pay $180.00 per month in partial *331 support. The amount awarded for child support is in the sound discretion of the trial judge and will be disturbed only where abuse of discretion is shown. Sawyer v. Sawyer, 21 N.C. App. 293, 204 S.E. 2d 224 (1974). No such abuse of discretion has been shown in the present case. Although defendant-mother’s expenses exceed her income even before the support payment is made, plaintiff-father is in no better financial position. It is apparent from the findings that the trial court took the needs of both parties into consideration, as well as the monthly needs of the children, and apportioned the duty of support accordingly.
¶4 Defendant-mother has also presented the argument on this appeal that the 2 July 1976 separation agreement entered into between the parties precludes any award of child support. That question is not properly before this Court, since the agreement was not made a part of the record in this case. However, even if the parties did so contract, their agreement could not operate to remove the children completely from the protective supervision of the courts in regard to support. Bunn v. Bunn, 262 N.C. 67, 136 S.E. 2d 240 (1964); 2 Lee, North Carolina Family Law, § 189, pp. 395-396 (1963). A provision in a contract between the parents relating to support of their children would only be presumptively just and reasonable, subject to change by the court upon a showing of need. Fuchs v. Fuchs, 260 N.C. 635, 133 S.E. 2d 487 (1963).
¶5 For the reasons stated, the order appealed from is
¶6 Affirmed.