Barnes, Presiding Judge. Faith M. Calvert (“the mother”) appeals from a trial court order modifying custody and child support for the three minor children she shares with her former husband, Jerome L. Calvert (“the father”). The mother contends that the trial court abused its discretion by awarding the father primary physical custody of the two youngest children, as he had not sought that relief in his petition. She further asserts that the trial court erred when, in calculating child support, it credited the father for the children’s health insurance premiums paid by his current wife, but failed to credit the mother for the health insurance premiums she paid to cover the children. Finally, the mother claims that the trial court erred in modifying the father’s payment schedule for the past due child support owed her. For reasons explained more fully below, we find no error and affirm the trial court’s order as to child custody, child support, and the proposed payment schedule.[1] In deciding child custody, “a trial court has very broad discretion, looking always to the best interest of the child.” (Citation and punctuation omitted.) Taylor v. Taylor, 293 Ga. 615, 616 (1) (748 SE2d 873) (2013). When we review a custody determination, we view the evidence presented in the light most favorable to upholding the trial court’s order[,] . . . mindful that the Solomonic task of assigning the custody of children lies squarely upon the shoulders of the judge who can see and hear the parties and their witnesses, observe their demeanor and attitudes, and assess their credibility. If the record contains any reasonable evidence to support the trial court’s decision on a petition to modify custody, it will be affirmed on appeal. (Citation and punctuation omitted.) Mitcham v. Spry, 300 Ga. App. 386, 386-387 (685 SE2d 374) (2009). The record shows that the parties married in 2008 and were divorced pursuant to a final judgment and decree of divorce entered in December 2013. The divorce decree granted the mother primary physical custody of the couple’s only minor child, C. F. C. (born in 2008), and required the father to pay child support. Several months after the divorce, the parties reconciled and resumed living together as husband and wife, although they never remarried. During the time they lived together, the parties had two more children, C. L. C. (born in 2014), and C. J. C. (born in 2016). The mother and father separated a second time in January 2020, and all three children remained with the mother. One year later, the oldest child went to live with the father and in April 2021, the father filed a petition seeking legitimation of the two younger children; joint legal and physical custody of and visitation with the two younger children; primary physical custody of the oldest child; and modification of his child support obligation with respect to the oldest child. The mother counterclaimed for joint legal custody and primary physical custody of all three children. She also sought child support for all three children and an award of attorney fees under OCGA § 1962. Several months after the father filed his petition, the mother filed a motion for contempt based on the father’s failure to pay child support as ordered by the divorce decree. She also sought attorney fees for the cost of bringing the contempt motion. The father, in turn, moved for the appointment of a guardian ad litem “to render an opinion as to what is in the best interest of the children with respect to primary legal and physical custody.” Following a hearing, the trial court entered an order on May 10, 2022 that, among other things, granted the motion for appointment of a guardian ad litem; found the father in contempt for failure to pay child support as required by the divorce decree; and awarded the mother $21,825 in past due child support and $4,315 in attorney fees. The order required the father to pay the attorney fees within 30 days and to pay the mother $500 per month in past due child support until the balance was paid. In December 2022, the guardian ad litem sent a written report to the parties in which he recommended that the father be given primary physical custody of all three children. After detailing his concerns, the guardian ad litem concluded: Based on all of the above concerns, as well as others that have come to [light] during this investigation, I believe that the environment that the children would be in at their father’s house would be more stable and beneficial to the young[er] girls. . . . This Guardian cannot help but be somewhat influenced by the fact that [the oldest child], on her own decision, has moved in with her father and is thriving more so than when she was living with her mother. The two younger girls, I believe, require structure, and their time needs to be better controlled, than what appears to be occurring at their mother’s home. I believe, therefore, that it is in the best interest of these girls for primary custody to be awarded to their father . . . .
