In addition to periodic support payments, the court may require that an obligor pay a designated percentage of a spouse's reasonable and necessary health care expenses. If health care coverage is available through an obligor or obligee at no cost as a benefit of employment or at a reasonable cost, the court shall order an obligor or obligee to provide or extend health care coverage to a spouse. Upon failure of the obligor to make this payment or reimburse the spouse and after compliance with procedural due process requirement, the court shall treat the amount as arrearages.