Relationships that end often leave us wondering why

She stood next to me on my wedding day. She dropped everything to be by my side for a week after I was in a tragic car accident.

She always knew what to say and, more important, when to say it.

But over a period of a few months after nearly a decade of friendship -- which included thousands of daily e-mail messages, hundreds of phone calls, nearly a dozen romantic breakups between the two of us, and several gabfest, girls-only vacations -- she disappeared from my life without an explanation.

I once thought we had been through so much together nothing could ever come between us. Now I'm left alone, silently wondering what I said wrong or what I didn't do right, wishing I could take back whatever I did.

Turns out, I'm not alone. Many women have a tale of some kind of friendship breakup, often a significant one like mine that goes unexplained, leaving a void that's hard to fill.

Had it been a romantic break-up, I might not have suffered in silence. My support system would have rallied, ready to analyze unseen red flags, validate and understand my pain or offer their failed friendship woes.

But unlike romantic breakups, friendship breakups have been, up until recently, almost taboo to discuss. In a perfect world, friendships are supposed to last forever.

Now Oprah is talking about it. Books are being written about it. Web sites have popped up to share heart-rending stories about them.

"I wrote this book to help dispel the embarrassment and shame that too often accompany failed friendships," writes Jan Yager, author of "When Friendship Hurts" (Simon & Schuster). "For some, admitting to a broken friendship has become like admitting to a failed marriage."

Los Angeles writer Liz Pryor started talking after her close friend Maggie faded out of her life.

"I couldn't figure out why," she says. "I spent about a year thinking about how I felt about it. Finally, I started talking about it. I really, really was convinced that I was the only woman going through this. But once I started opening up in intimate circles, everybody responded with 'Yes, I've had one of those.' "

She poured her pain into a book called "What Did I Do Wrong? When Women Don't Tell Each Other the Friendship is Over" (Free Press). Through her research for the book, she's sorted through hundreds of stories of failed relationships, many of which she has posted on her Web site, www.lizpryor.com, from other women who have had similar experiences.

"So many women do have one woman in their life as a friend that they've lost," says Hillsborough writer Leah Stewart, who last year wrote "The Myth of You & Me" (Shaye Areheart Books) basing the fictional book on a lost friendship, an experience that Stewart went through herself.

"It was something that I still thought about years later," she says of the breakup. "I wondered if it was an experience that would translate to readers."

Her Web site (www.leahstewart.com), too, is full of stories from readers who understand. Like Courtney, just last month, telling us about rekindling with Anna after Anna went out with Courtney's husband during Anna's divorce. Or the jealousies that split up Jody and Beth.

Most friendships, however, aren't ended over one or two problems. It's usually a series of problems that are never addressed, Pryor says.

When she was able to interview both women involved in a failed friendship, she found that often the initiator of the breakup had reached that "final straw" stage, where one final indiscretion pushed her over the edge. "She would say it was a huge compilation of things rather than just one thing," Pryor says.