Kristi McLeod (plaintiff) and Robert Starnes (defendant) were divorced after five years of marriage. As part of the divorce decree, Kristi was awarded custody of the Starneses’ two minor children. Robert was required to pay weekly child support, which was later reduced by an agreement between Kristi and Robert. Additionally, Robert was ordered to pay a portion of his annual bonus as child support. Over the years, Robert’s salary grew significantly, from approximately $32,000 to nearly $250,000. Kristi’s income grew from $14,000 at the time of the divorce to nearly $40,000. Despite the sizeable difference in income, Kristi never sought to modify Robert’s child-support obligation. When their oldest child, Collin, enrolled in college, Robert agreed to repay all student loans upon Collin’s graduation and unilaterally reduced the monthly child-support obligation by $75. Kristi did not object. However, when Robert failed to pay for Collin’s college expenses, Kristi filed suit, seeking payment and increase in child support for their younger daughter, Jamie. Robert filed a counterclaim to terminate (1) the child-support obligation for Collin, who had reached the age of majority and graduated from high school; (2) the child support for Jamie once she graduated from high school; and (3) the requirement that Robert pay a percentage of his annual bonus as child support. Robert also claimed that the requirement to pay for Collin’s college expenses violated equal protection. The trial court dismissed Kristi’s claim for payment of Collin’s college expenses on the ground that the payment violated equal protection. Kristi appealed.