Does "couple" (married people) agree with the plural or singular verb?
When used to refer to two people who function socially as a unit, as in a married couple, the word couple may take either a singular or a plural verb, depending on whether the members are considered individually or collectively: The couple were married last week. Only one couple was left on the dance floor.
When a pronoun follows, they and their are more common than it and its: The couple decided to spend their (less commonly its) vacation in Florida. Using a singular verb and a plural pronoun, as in The couple wants their children to go to college, is widely considered to be incorrect. Care should be taken that the verb and pronoun agree in number: The couple want their children to go to college.