Kirstie Alley(Michael Carpenter - WENN.com)

There's nothing wrong with a little competitive spirit - but Kirstie Alley is displaying some serious unsportsmanlike behaviour these days.

The Dancing with the Stars: All Stars contestant is pulling out all the stops to stay in the competition - and turn her new memoir into a bestseller - by dishing out details of her personal life that could have devastating consequences on others.

The 61-year-old actress has dropped several bombshells while promoting "The Art of Men," including a claim she and the late Patrick Swayze fell in love on the set of North and South in 1985.

"Both of us were married," she told Entertainment Tonight, stressing the affair was strictly emotional. "But again, I think what we did was worse," she said. "Because I think when you fall in love with someone when you're married, you jeopardize your own marriage and their marriage. It's doubly bad."

Despite the fact Swayze isn't around to defend himself having died of pancreatic cancer in 2009, the same year he renewed his wedding vows with wife of 34 years Lisa Niemi, Alley saw fit to tell Barbara Walters he'd pushed her to divorce then-husband Parker Stevenson so they could be together.

"I probably was more willing to break up my marriage and I wasn't willing to break up his marriage," she said.

While Alley says she's not sure if Swayze's widow knows about their relationship - she sure does now! - the actress insists she's good friends with Liemi and was even asked to speak at Swayze's funeral. With friends like these...

And while it's clear Alley's thirst for a top-selling memoir has overruled her sense of right and wrong, it's not just Swayze's widow she's hurt by leaving with unanswered questions, but also her ex-husband of 13 years, who she seems to brush off as a mere seat filler between her other "greatest love" John Travolta, who "isn't gay" by the way.

Some secrets should be taken to the grave and if Alley's moral compass was functioning properly, it would have told her to steer clear of the entire Swayze subject.

But the former Cheers star isn't the first and she won't be the last to sensationalize their love lives for profit, no matter what the cost to others.

Arnold Schwarzenegger revealed an affair with Brigitte Nielson in his recent "Total Recall" autobiography even though ex Maria Shriver was taken by surprise by the news, already beaten down by his epic cheating scandal with the family nanny.

In her memoir "Kris Jenner...And All Things Kardashian," the reality TV momager confessed it was her affair that ruined her marriage to Robert Kardashian, even though the news came as a shock and upset some of her children.

And despite it being a tad awkward for his wife to hear, Jean Claude Van Damme boasted about "beautiful lovemaking" with singer Kylie Minogue during an affair on the set of 1994's Street Fighter, while out promoting Expendables 2 this summer.

Kissing and telling is fine and dandy - in fact, we encourage it! - but not when the titillating details have the potential to cause more harm than good.