One loves, the other is loved-not. Don’t mistake raging lust for true love. Two half-people don’t make one whole.

Does this sound familiar? They should.

These refer to some of the most frequent problems encountered in the bloody arena of relationships. These also happen to be some of the themes covered in Sherry Amatenstein’s new book, Love Lessons from Bad Breakups.

Amatenstein, a dating columnist on iVillage.com, gives us access to 21 disastrous relationships that were simply incompatible or seriously dysfunctional. She observes the wound, then plucks out the splinters for us to see.

Love Lessons dedicates a chapter for each relationship, furnished with dates of their birth and demise. It is told in the classic “he-said/she-said” fashion. Amatenstein states the problem, notes where they erred and where they shone, then concludes with priceless love lessons from the breakup.

As most of us know, a small argument is just as effective as an earth-shattering mistake in upsetting the cosmic balance of our romantic destiny.

Unrealistic expectations, narcissistic beliefs, chronic infidelity and even unattractive potbellies got in the way of these relationships.

In the story, “Don’t Mistake Raging Lust for True Love,” Rachel endured four years of marriage with a cheating lover because he was “cute.”

In “Ignorance Isn’t Bliss,” Tom is a full-fledged homosexual who married Diana because he could “pull the wool over her eyes.” In their 10 years of being best friends, great lovers and awesome parents, Diana never knew (or refused to heed the signals) that Tom preferred men from day one. Ouch.

Unrequited passion turns an ideal match into a romantic dead end in “One Loves, The Other Is Loved-Not.”

Starry-eyed Samuel would have groveled at Barbara’s feet if she asked him to.wait, that’s exactly what he did.

Unfortunately, great business partners don’t necessarily make great lovers, especially if one of them doesn’t even feel a smidgen of desire for the other. Six years of anguished poetry later, they break up. “If I hadn’t ended it, we’d be like two old farts roaming around an overgrown garden,” Barbara said.

Meanwhile, the maddeningly idealistic Samuel still roams the world, doomed to mourn his “immortal beloved.”

Now there’s your classic love tragedy. Where’s the tissue?

Soul mates, sexual chemistry and rose petal-strewn beds aside, these messy breakups on Love Lessons teach all the hackneyed but true sayings: Love isn’t a fairy tale. Communication is the key. You can’t have your cake and eat it, too.

Two stories about revived relationships are the only exception to this series of bad breakups.

Amatenstein proves to be lighthearted, sometimes funny, but always perceptive.

She makes fair, reasonable judgments about the couples and how their upbringing, values and apprehensions contributed to their downfall.

However, the most fascinating thing is how she found couples who were actually willing to share their battle scars with readers. It is a bit amusing to notice each person’s distorted storytelling, but they seemed earnest in their attempts to rehash the gory details for our enlightenment.

Overall, Love Lessons is an interesting book packed with invaluable insights. It is easy to read, as well. You might not buy into the whole idea of self-help literature, but you will surely learn a thing or two here. Who knows, you might need them one day.

After all, the best advice on how to survive relationships may come from those who didn’t.

Grade: A-