Power Couple Split After Racy Bachelor Party; Ex-Fiance Sues for $60,000

March 16, 2011— -- Weeks before her planned wedding, Lauren Serafin says she learned her fiancé Robert Leighton likely had an illicit encounter at a bachelor party in Las Vegas.

Now the former couple may be headed to court after Serafin slapped her alleged philandering fiance with a complaint in the Circuit Court of Cook County, Ill., for breach of promise to marry and other relief.

The bride and groom were close to tying the knot when Serafin alleges in the suit that she discovered text messages sent to her fiancé indicating "something happened" during his trip to Sin City.

After weeks of denial and numerous attempts to discretely move out of the couple's shared apartment, Robert Leighton confessed to "hooking up" with a woman named in the lawsuit as Danielle, according to court papers.

In the suit, posted on the legal news Web site On Point News, Serafin says the couple had a two-year relationship before Leighton proposed in July 2009. The following year, weeks before the "I dos," Leighton traveled to Las Vegas with family and friends for a bachelor party.

And, this is where things get murky. The complaint alleges Leighton and Danielle met "less than 24 hours prior to engaging in sexual intercourse."

The former fiancee claims that though she found text messages between Leighton and Danielle, her fiancé denied anything happened, apparently believing the mantra "what happens in Vegas, stays in Vegas."

In the following weeks, Leighton would allegedly admit he "made out" with the other woman, Danielle, before eventually disclosing the two "hooked up." Leighton would go on to blame Serafin for his indiscretion before informing the want to-be bride that he would not marry her, the court papers allege.

Since ending their engagement Serafin says she has suffered humiliation and depression and is seeking $62,814 as reimbursement for wedding preparations.

In a complaint to the court, filed by her attorney Enrico J. Mirabelli of Nadler, Pritikin, & Mirabelli, the jilted bride alleges breach of promise to marry and intentional infliction of emotional distress.

Leighton did not respond to ABCNews; Serafin and her lawyer did not respond to phone calls or e-mails.

Leighton and Serafin work at established law firms in the Chicago area and are 2008 graduates for Loyola University School of Law. Serafin, is an associate handling workers' compensation issues at law firm Hennessy & Roach. Leighton is an associate practicing intellectual property at the Chicago office of the global law firm Sidley Austin, which was the romantic starting point for now President Barack Obama and his wife Michelle Obama.

Since calling off the wedding, the suit states Serafin "made a demand for payment of the said expenses incurred prior to the filing of this lawsuit, and the defendant has refused and continues to refuse to pay said expenses caused by his breach of promise to marry her." The suit claims, Leighton had a "fiduciary duty of implied fidelity" to his then future bride. And, the complaint calls Leighton's conduct "extreme, intentional and outrageous" that "went beyond the bounds of decency."

The former bride-to-be is seeking damages for a laundry list of items that were a part of the couple's planned 170-person wedding on August 21, 2010.

That includes money spent on her wedding dress, invitations, the couple's planned honeymoon, and everything from a deposit on a banquet hall to catering by the Chicago Ritz Carlton.

"There has to be a division of compensation. Whatever the costs are they need to split them," says Karen Stewart, president and CEO of Fairway Divorce Solutions, who is not involved in this case. If the allegations are true, "she should be thankful she found out now. It was probably a cheap lesson. Once a cheater, always a cheater."

Stewart goes on to say, "I'm not a believer in victims. She at some level attracted somebody of this personality --somebody who cheats -- that's part of their core value system."

Her advice: Take half and "thank your lucky stars it cost you $30,000 because if you married him that would have cost you more," says Stewart.

Will the couple go to trial? "Attorneys understand the cost both publicity and financially to having a lawsuit played out in the public. On the other hand because the kind of lawsuit is emotionally driven sometimes people can't think of anything else but proving they're right," says Linda Lea Viken, president of the American Academy of Matrimonial Lawyers, who is not involved in the case .

"If the facts in the complaint are true there is a cause of action for the breach of the promise to marry and it appears there is a sufficient evidence for the intentional infliction action."