If one true thing can be said about love stories, it's that we love them.

We eat them up, whether they're truly awful (like those romance novels with Fabio on the cover) or awe-inspiring (for me, that would be Pride and Prejudice).

I did a search and found that Barnes & Noble is selling more than 20,000 books with the word love in the title. And even though some of these have nothing to do with romantic love, we're still dealing with a lot of books.

Love stories make up some of our oldest literature and mythology. Take the Egyptian goddess Isis, for example.

Worshiped throughout Egypt as long ago as 1500 BC, Isis was the goddess of motherhood and marital devotion, among other things. One of her most notable achievements was bringing her husband Osiris back to life after he was brutally murdered by his brother.

As old as this story is, I've always found it really touching. If you had the power, wouldn't you resurrect your murdered spouse?

Another ancient tale is the Odyssey, the story of Greek hero Odysseus's ten-year journey home from the Trojan War. Packed with adventure, this 2,800-year-old story has at its heart the importance of home and family, and how these forces are enough to help a man cross oceans and slay monsters.

The people who really perfected the telling of love stories were the troubadours, lyric poets, and poet-musicians who flourished in 12th-century France and sang tales that have been borrowed by writers many times since.

But what's striking about love stories is that when you really think about it, there aren't all that many love story plots. The same ones seem to be recycled again and again, in everything from coffee commercials to cartoons. And the vast majority of them--in my humble opinion--have a major flaw, which I will talk about later.

For now, though, let's take a walk through the love story hall of fame.

Forbidden love (and doomed love)
This is a classic love story formula. Probably the most famous example was written about 400 years ago: Shakespeare's Romeo and Juliet. These "star-cross'd lovers" were forbidden to love one another because of the ongoing feud between their wealthy parents.

As famous as Shakespeare's version of the story is, though, he wasn't the first to tell it. He based the play on a 16th-century English poem by Arthur Brooke called The Tragicall Historye of Romeus and Juliet. And this poem was based on an old Italian story. So clearly the idea had been around.

The love triangle
Forbidden in a different sense is the love triangle. My favorite version is the tale of King Arthur. One of the most famous leaders of all time, Arthur was the commoner who pulled the sword from the stone (or in some versions of the story, from an anvil) and became the ruler of Britain. With a grip like that, you'd think he'd be able to hold onto his marriage. But no. Arthur's wife, Guinevere, fell in love with his most powerful knight, Lancelot, and their affair split Camelot apart.

Love from afar (also love at first sight)
You know how this one goes. Their eyes meet across a crowded room and--shazam! It's love. This is the Cinderella story, or if you don't have any patience for people who accessorize with glass, it's the tale of Pepe LePew, the French skunk of Warner Brothers cartoon fame. Pepe repeatedly falls in love with a beautiful black cat who--thanks to cartoon magic--gets a white stripe painted down her back in every episode.

What I love about Pepe LePew is that he points out how silly love at first sight really is. He keeps falling in love with a cat, not a skunk--a great commentary on how our eyes can make us want what is utterly unsuitable.

Transforming love
A great love story plot is the one where the power of love makes one or both partners better people. You'll find this in Jane Austen's Pride and Prejudice, where both Elizabeth and Mr. Darcy make mistakes that nearly cost them their love but eventually are humbled and reunited to live happily ever after.

It's not just the old writers, though, who like the idea of love transforming. If you saw As Good as It Gets, you will remember hearing Melvin Udall (Jack Nicholson) growl, "She makes me want to be a better person," as he falls in love with Carol Connelly (Helen Hunt).

Triumphant love
The Odyssey, of course, is a great example of how love triumphs over all--from angry gods to one-eyed monsters to greedy suitors. Just about every love story with a happy ending is partly about triumphant love.

There's a variation on this, too: the version where two people overcome obstacles together, then fall in love as a result of their journey. This happened on the big screen in the movie Speed, where Keanu Reeves the cop falls for Sandra Bullock's accidental bus driver.

Where love stories break down
This speedy kind of love gets right at the problem with all these romance paradigms: They tend to end right at the point where either love is consummated or the lovers die. And that's not how it works in real life. Even in Speed, the characters acknowledge the folly of their budding relationship, but they go ahead and kiss anyway.

Real-life love, the kind that leads to 50-year marriages, has different challenges and requirements. It may start with the kind of love you read in books and see in movies. But to find out how the rest of the story is supposed to go, we're pretty much on our own.

Or so I thought, until I talked with Raymond Cormier, a visiting professor at Longwood College in Virginia. Cormier helped me come up with the love story paradigms I mention above and is an expert in love. Not only has he studied courtly love for decades, he's also been married for 40 years. And he has three tips for how "happily ever after" actually works:

• Find a friend, someone you can live with. After 40 years, romance becomes less of a priority.
• Give your partner space to develop as a human being.
• Respect each other.

Mutual respect doesn't look all that exciting on the big screen, but Cormier points out that there are some great old stories illustrating this kind of love.

There's Chrétien de Troyes' Ywain: the Knight of the Lion, a 12th-century romance about a knight who leaves his wife and fails to return by his deadline. So she kicks him out, and he must redeem himself through suffering before their love can burn again.

And then there's Chrétien's tale of Erec and Enide, who find their love falling flat after an exciting courtship. So they go on some adventures together, and their love is reborn.

These stories might not be in the love hall of fame, but wouldn't you like your own love story to turn out as well?