Oddly enough, I've read a few romance novels (well, I read just about anything I can pin down) and you're right that there is a strong element of instruction in them. There may not be a paragraph on the last page which says "and the moral is..." but it's implicit.
From what I've seen, romance stories are either reinforcement tales: Do this and not that, and you'll be rewarded. Or they're martyr tales: one bad thing happens after another that's not our character's fault, stay tuned to see how long we can stretch this out. It's an interesting genre, with its own rules and conventions just as established as those for mysteries or Westerns.