The Horse and His Boy (Chronicles of Narnia 5)

Aravis also had many quarrels (and, I'm afraid, even fights) with Cor, but they always made it up again: so that years later, when they were grown up, they were so used to quarrelling and making it up again that they got married so as to go on doing it more conveniently. And after King Lune's death they made a good King and Queen of Archenland and Ram the Great, the most famous of all the kings of Archenland, was their son. Bree and Hwin lived happily to a great age in Narnia and both got married but not to one another. And there weren't many months in which one or both of them didn't come trotting over the pass to visit their friends at Anvard.