(CNN) -- Contrary to the popular playground song about sitting in a tree (and K-I-S-S-I-N-G), marriage doesn't always come after love.
I know what you're thinking: "Engagement" and "carriage" don't rhyme. But with so many couples postponing their "I do's" in favor of longer engagements, the chant could afford to be updated.
Despite the "The Five-Year Engagement's" lackluster opening weekend, the film touched on a cultural phenomenon that's been adopted by modern couples such as Mar Yvette and Aram Brazilian, who will have been engaged for 11 years come Saturday.
"We had an engagement party ... but there was never any talk of setting a date," said Yvette, 35. "What was really important to me, and what made it special and possible for us to live together, was the fact that he asked me to marry him."
Brazilian, 43, said, "The idea of walking down the aisle, dressing up in the tuxes, it seems a little bit contrived. As far as spiritual reasons, we don't feel like we're doing anything wrong. We're not ruling (getting married) out. ... Mar likes having her own identity and being her own person, and I don't have a problem with that. She knows I'm not going anywhere, and I know she's not going anywhere."
Engagements traditionally lasted no longer than six months, according to Helen Fisher, a biological anthropologist at Rutgers University and chief scientific advisor of Chemistry.com, and they were at one point viewed as pit stops on the way to marriage. Now, she added, the post-proposal time period is considered its own step in the mating process.
"In the '60s, you got engaged in the fall and had a spring or summer wedding," Fisher said. "In those days, people would probably think a year-and-a-half-long engagement was long. Now we think a five-year engagement is long."
"What's happening with this movie, and our modern world, we're saying we are going to define engagements differently," Fisher said. "We're no longer defining it as a concrete steppingstone to marriage. We're defining it as a more solid relationship of living together."
As Yvette said, "If it's not broke, don't fix it."
"We're in a loving, committed, happy relationship," she said. "The only pressure I feel is from outside sources. From friends saying, 'Well, when are you going to get married?' And also our parents. My parents would really love it because I'm their only daughter."
Yvette said she used to tell people she'd eventually get married to make them feel comfortable.
"I just never had this strong urge to be Mrs. So-and-So," she said. "I mean, I have the ring and everything, and to me that's really special. ... We do, by all accounts, live like a married couple."
Just as some people view getting engaged differently in 2012 than they did a mere decade ago, living together is now regarded as a permanent state for many couples.
According to the 2010 census, the unmarried partner population numbered 7.7 million, up 41% since 2000.
"We don't have to be married to enjoy many of the benefits that traditionally were exclusive to marriage," said Susan Brown, co-director of the National Center for Family and Marriage Research at Bowling Green State University in Ohio. "Cohabiting for example ... sexual partnerships. Sharing of a household. Having children."
That's one reason the average age of first marriage is the highest it's ever been, Brown added.
According to the U.S. Census Bureau, the estimated median age at first marriage in 2011 was 28.7 for men and 26.5 for women, compared with 26.8 and 25.1, respectively, in 2000. Marriage is also on the decline -- 54.1% of adults were married in 2010 as opposed to 57.3% who were married in 2000.
"(A couple) may never want to marry, but they may want to tell the world, 'This is a solid relationship,' " Fisher said. "Definitions are changing."
But not all couples are content in a state of engaged bliss. Saving money for the wedding, moving to a new city or starting a new job are all factors that might delay a walk down the aisle.
More couples are paying for their own weddings, said Anja Winikka, the site editor of WeddingChannel.com. "What's a few more months for the dress you want or the venue you want? Don't go into debt over your wedding," she added.
"From a wedding planning perspective, 12 months is kind of the magic number," Winikka said. She even recommends that brides choose their dresses up to eight months in advance if they want the "bridal salon experience."
Brianna Smith, 24, and Daniel Neenan, 27, who will have been engaged for one year on May 30, plan to tie the knot on May 26, 2013. The couple started dating in January 2009.
The Long Island-based pair's two-year engagement wasn't so much about a perfect season or venue. Rather, it was about saving money for the big day.
"I personally like having a longer time (to plan) so I don't have to stress about everything. We wanted to enjoy our engagement," Smith said, adding that she and her fiancé didn't plan anything the first few months they were engaged.
"My parents dated for six months, and six months later they were married, which I think is ridiculous right now," Smith said. "Longer engagements are the new thing."
Fisher said, "We live in a time where you can do it the way you feel comfortable doing it. There are some people who want to make a deep, long-term promise to each other, which is an engagement, and marry 10 years from now."
The redefinition of the term "engagement" is creating a new frontier for longtime committed couples. "The day is going to come when we look back at somebody who instantly married and wonder why," Fisher said.