In the sci-fi series Firefly, two of the main characters--tough-girl first mate Zoe and goofy pilot Wash--are married to each other. They start the series as a long-married couple and they finish it married. They're obviously nuts about each other and they have plenty of sex, and they don't go through any drama with their relationship.
Or rather, they go through lots of drama--attacks by crazed space barbarians and traitorous space pirates and the evil space empire--but their relationship is stable through it all. The series isn't about their relationship; it's about wacky space action and they just happen to be happily married.
(I acknowledge that this is probably because the series didn't run long enough for Joss Whedon to put them through the most miserable, wrenching breakup imaginable, and he probably only kept them together so long so it would hurt more. But let's work with what's on the screen, not what we damn well know was coming.)
Zoe and Wash's marriage made me realize how rare this is in fiction--the depiction of a stable couple as still being interesting people. So often, the formation of a couple is the end of the story--our hero got the girl, credits roll. It's rare enough to see "our hero got the girl, but they still have space pirates to fight," much less "our hero got the girl before the story even started, but they still have space pirates to fight." (It's also significant that Zoe and Wash got together because they were attracted to each other, not because Wash was so good at fighting space pirates that he "got" Zoe.) The idea that life and struggle don't culminate in love, but that your story continues after even you fall in love, is very rarely found in Hollywood.
And it's too bad, because in real life, relationships are not the end. The credits don't roll and you don't get to enter your high score. Life doesn't get magically easier or simpler, and the relationship itself is an ongoing process. Love becomes not a reward that you can sit back and enjoy, but a part of your life. (Oh, and people in relationships still have sex like whoa.) So you're in love, true lasting love; good for you, but together and on your own, you've still got a hell of a lot of battles left to fight.