By Emily Feimster Hollywood's a whirling dervish of beautiful people going in and out of relationships but some couples just can't seem to stay apart. One minute they're trashing each other in the tabloids, the next minute they're making out in public. Though some celebrities never accept the fact that the relationship is over, others eventually move on. Even Elizabeth Taylor and Richard Burton finally threw in the towel after being married twice. So jump on the merry-go-round of love, but hold tight, as we take a look at who's calling it quits and who's hanging in there in Hollywood.

No two people exemplify the on-again/off-again relationship more than Pamela Anderson and Tommy Lee. The "Baywatch" babe and Motley Crue drummer wed in 1995, on the beach, in bathing suits, just three days after meeting. They went on to remarry shortly after, wearing space suits. (Wow, if that wasn't a sign that their marriage was doomed, then we don't know what is). Two months after their son Dylan was born, Pamela filed for divorce after Tommy assaulted her. He was sentenced to six months in jail. Astonishingly, the couple continued to date, even though the actress discovered she had hepatitis C from when they shared the same tattoo needle. Though they've had their share of other companions, the ill-fated lovers were spotted just last month vacationing together in Hawaii, but Pamela claimed she was just trying to help ole' Tommy generate press for his reality show. Riiight.

The super cute Orlando Bloom and Kate Bosworth announced they were ending their two-year relationship in January to concentrate on their careers, but the pair still can't seem to separate. Though Bosworth was rumored to be dating a director's assistant on "Superman Returns," Bloom flew to Australia to visit her on set. In fact, his actress sister, Samantha Bloom, insisted the pair was still together - as of July, that is. "They've been together for two years and they are still very much together." More recent reports claim that Bloom enjoyed a romance with his "Elizabethtown" co-star Kirsten Dunst, but both deny the accusation.

Don't think Dunst hasn't had her own share of ups and downs with her long-term love Jake Gyllenhaal. After dating for two years, they officially split in June of 2004, but have been spotted together many times since. She said in an interview, "I don't believe we're finished for ever and neither does he. But I felt that at the age of 22, I just wasn't ready to settle for a long-term commitment." That certainly doesn't keep them from PDAs every now and then.

It was only last year that Gyllenhaal's "Brokeback Mountain" co-star Heath Ledger finally brought his relationship with Naomi Watts to an end. The Aussie pair, who met on the set of "Ned Kelly," started dating in 2002, but split six months later when the much younger Ledger admitted he wasn't ready to settle down. A week later they were seen making out in a restaurant. They lasted for another eight months before splitting due to their hectic work schedules, but were back together again weeks later. Come on, people! They officially split in 2004. Ironically, the once commitment-phobic Ledger is expecting a baby with his current girlfriend Michelle Williams.

Other couples who haven't seemed to be able to make up their mind include Leonardo DiCaprio and Gisele Bundchen, who are currently basking in being together, as well as "Scrubs" star Zach Braff and his once off, but now on girlfriend Mandy Moore. The on-again/off-again couple who wasn't as lucky in love is none other than Ben Affleck and Jennifer Lopez - A.K.A. Bennifer. It took them canceling their wedding not once, but TWICE before accepting the fact that they were the worst paired match ever!

Of course some reconciliations are still up in the air. Though Charlie Sheen cleaned up his act, he still couldn't keep his wife Denise Richards from leaving. In March, the pregnant Richards filed for divorce after three years of marriage. According to Sheen, it ain't over till it's over. The couple has reportedly been attending counseling sessions for the past two months, hoping to give their marriage a second chance. He told the TV show, "Extra," that reconciliation is "possible. Things were bad, obviously, and things are a whole lot better, and I think with that is hope and whatever the future might deliver, we both embrace... We're not ruling anything out."

In the meantime, fans can't help but wonder what will happen between the recently engaged Jude Law and Sienna Miller. The British actor shocked the world when he announced he had been cheating on Miller with his children's nanny. However, in recent weeks the couple has been spotted on romantic dates with each other in London. As they say, once a cheater, always a cheater, but nobody ever asks us! Only one thing's for sure, though - if this couple is anything like the rest of these folks, it could be a long time before they finally call it quits.