ABC News' Anna Wild and Katie Kindelan report:
First comes love, then comes marriage, but before any of that, in many cases, comes the pre-nuptial agreement. And in today's world, the conditions of what will happen if a couple does, in fact, part before death, are becoming more and more extreme.
The high-stakes world of high-end pre-nups was immortalized on the small screen in "Sex and the City" when Kristin Davis's character, Charlotte, declared, "I'm worth a million," to her fiance's mother in negotiating an increased post-divorce payout.
In real life, Rosie O'Donnell most recently made headlines last month when the New York Post's Page Six reported the comedian's "11th hour extreme prenup" with fianceé Michelle Rounds came after eight months of "grueling" negotiations that, according to the Post, ended with a clause forbidding Rounds from receiving any of O'Donnell's wealth if she cheats.
It's not just celebrities or TV characters who include a contract alongside their wedding vows, however.
The New York Post recently reported on some of the more outlandish demands made by the clients of top New York City divorce lawyers and matchmakers, including frequent clauses that the respective partner stay skinny and one demand that the wife not cut her hair.
"One man dictates four home-cooked meals a week or the wife loses her shopping allowance in New Jersey," Patti Stanger, the host of the Bravo TV reality show "Millionaire Matchmaker" told the Post, adding that another client signed an agreement that she would never wear green and, if she did, her husband was allowed to destroy the item.
Gregg Sullivan and his longtime girlfriend, Toni Mantus, both New Yorkers, have gone so far as to work out an agreement, even though they have no plans to marry, but to just remain committed in their relationship.
"The thing that always scared me away from marriage is a concern that after people get married they change," Sullivan told ABC News. "I believe staying trim and healthy is very important, and part of my agreement with Toni right now addresses that. I believe it's just as important for a woman to maintain herself and her health as it is for a man."
"An inequity that I'm seeing everywhere, and it's called the fidelity trap, is that now that you get married, the woman can change and doesn't have to take care of herself, or stay attractive, but if you were unfaithful, or had needs outside of the relationship, you're gonna get penalized," he said. "It almost gives a free ticket to the woman to say, Now I don't have to care anymore about myself, and that's scary to me."
Mantus, who has dated Sullivan for 12 years, understood her partner's concerns and also had a demand of her own, that Sullivan carve out time for her, away from work.
"I wanted him to take more time off of work, and he was a workaholic and had a lot of fires going, and I just wanted him to make time for us to go out," she said. "That was something that I asked him, that I requested of him, to go out regularly, to make a date night, to focus his time on things that benefit us as a couple."
As for Sullivan's request that she work on her figure, Mantus said she could see his point.
"He's worried about me not being who I was when he met me. I was into going out, dancing, and there has been a lot of stress over the years, that I haven't taken really good care of myself," she said. "So to agree to eat well and to go for walks and things with him, it's a benefit to both of us."
"You can really create any kind of agreement you want," she said of the idea of a pre-nup. "You can say, 'I want to make sure my partner gets this and gives these things and this is what I would like.' It's like when you write your own vows at a wedding. You write what you expect from each other."
Ann-Margaret Carrozza, a New York-based estate planning attorney, says Sullivan and Mantus' attention to detail, while it may seem unromantic now, may be what keeps their marriage together in the long run.
"I think that embarking upon a marriage, which is the most significant joint venture any of us will ever embark upon in our lives. We are picking china patterns, we're picking silverware, we're deciding where we want to live, and I think beyond that, we'd all be better off if we thought about what we want that life to be like," she told ABC News. "The time to deal with that may well be on the front end."
"Step number one with the pre-nup is what happens to the property in the event that the marriage doesn't work out," Carrozza said. "Step number two tries to define what the expectations are of each other's behavior within the marriage, and it can come down to the tiniest details such as housekeeping and taking turns with different chores, whose turn is it to pay the bills, and whose turn is it to schedule dinner with friends."