William: "I live in Notting Hill. You live in Beverly Hills. Everyone in the world knows who you are."

Anna: "I'm also just a girl, standing in front of a boy, asking him to love her."

        --Notting Hill

In the film Notting Hill, Julia Roberts' character, a mega-movie star, meets a lowly British travel bookshop owner played by Hugh Grant, and through a series of rocky jump starts, they end up together and live happily ever after. Sure, every real-life movie star out there wishes they could find their own lowly bookshop owner to live happily ever after with. If only the road to true love in Hollywood were that easy.

Sorry, it ain't happening, folks.

What is it about show biz couples? Why can't they stay together? Well, personally, I think it stems from the same reasons that brought them together in the first place--the completely out of control, make-believe world they work and live in.

Take your common workplace romance, which is often a very easy way to meet a spouse. You fall in love with your co-worker because you see him or her all the time. Now, imagine your job is to not only to make obscene amounts of money by being beautiful, talented, and then have everyone tell you how beautiful and talented you are, but on top of it all, it is also your job to make love to Russell Crowe in a romantic locale at the same time.

Right. Stay with me now...

Say, then, the two of you end up together; two ultra-beautiful people wandering around, going grocery shopping, buying a house, attempting to live what we peons consider a "normal" life--while millions of adoring fans watch every single move you make. Maybe one of you is more successful than the other--that shouldn't matter, right? Or perhaps one of you is secretly crazy--that could be overcome with help, yes? Or, of course, one of you inevitably makes another movie with another beautiful co-star... well, you see where that would lead.

Thus the tensions pulling apart celebrity couples are understandably heightened and not necessarily the same an ordinary person would feel. Let's take a look at some of those reasons and which movie star break-up fall in those categories.

Reason #1: Successful careers get in the way

Egos are a big thing in Hollywood--they are large and in charge and very much a problem, especially if one half of a couple is getting more recognition than the other. For example...

Kate Winslet & Jim Threapleton: The most recent couple to go belly up. Poor Kate, looking sad, carrying the couple's adorable daughter, telling the press she and her soon-to-be ex, Threapleton, an assistant director, are handling things amicably. What's really going on is that Threapleton didn't like being Mr. Winslet. He didn't want to be under her shadow anymore. Please. Like he has any chance now of getting his scripts read if he isn't married to a star like Winslet. That's just plain dumb thinking.

Julia Roberts & Benjamin Bratt: Julia is a tricky one because she gets very involved with her co-stars on the set. She's a flirt. Big deal. Ben is a big giant fool. I believe Julia would have followed him to the end of the Earth. She really looked like she loved the guy. But no, he's got to get into the big ego thing--tired of hanging on the arm of this huge Academy Award-winning actress. Grow up, Ben.

Reason #2: Meeting someone else

I tell you, being on a movie set in some exotic location, gazing lovingly at your co-star--that has got to rub off. Just look at:

Meg Ryan & Dennis Quaid : Meg met Dennis on the set of Innerspace and they fell madly in love, married, had a son. Then boom! Meg falls--and falls hard--for hunky Australian Russell Crowe on the set of their film Proof of Life late last year. It could be Meg and Dennis were already tiring of one another after 9 years of marriage; that happens. But Meg couldn't pass up the Crowe man, no way, no how. And Dennis couldn't turn the other way. Goodbye!

Elizabeth Taylor & everyone she's ever been with: Liz leaves first husband Nicky Hilton for actor Michael Wilding; she leaves Wilding for producer Mike Todd; Todd dies and Taylor takes up with singer Eddie Fisher (taking him away from Debbie Reynolds); dumps Fisher for actor Richard Burton, whom she met on the set of Cleopatra--a tumultuous love affair where she divorces Burton and then remarries him. Her last two husbands don't count, since she pretty much was out of the movie business by that time. However, Ms. Roberts, take note.