We've all heard the popular American rhyme about relationships: First comes love, then comes marriage, then comes baby in a baby carriage.

However, thanks to the current phenomenon of the 'hookup culture,' the traditional American family is rearranging to conform to the structure of modern, noncommittal relationships: first comes sex, then comes cohabitation, then maybe a baby, and possibly marriage.

In fact, the sequence of hooking up, sex, and premarital cohabitation seems to represent a growing norm in society, pointing to the fact that the traditional major milestones of a relationship are happening prior to marriage rather than after tying the knot.

Although the phenomenon of the hookup culture is often attributed to millennials, studies from the Journal of Sex Research have shown that millennials (2004-2012) do not actually have more casual sex than the generation before them (1988-1996).

With this in mind, it should be equally as enlightening to both millennials and non-millennials to hear that this culture of casual sex, the haze of hooking up, and the slide of sexual intimacy is also affecting the chances of a happy marriage.

The National Marriage Project at the University of Virginia published a study called "Before 'I Do'" and found that what couples do before they say 'I do' actually matters -- and that premarital experiences from the past could end up haunting them long into marital bliss.

"What people do before marriage appears to matter," stated Dr. Galena K. Rhoades and Dr. Scott M. Stanley in the 2014 study, saying that "how they conduct their romantic lives before they tie the knot is linked to their odds of having happy marriages."

Rhoades, a Research Associate Professor in the Psychology Department at the University of Denver, and Dr. Scott, a Research Professor and Co-Director of the Center of Marital and Family Studies at the University of Denver, have spent their time researching relationship commitment and development, as well as related implications for family, children, and divorce.

Their findings lead to the conclusion that happy marriages could weigh on the balance of relationships past.

They found that those couples who partook in hooking up, premarital cohabitation, or even engaging in multiple sexual encounters with different people over the course of their lives would have a less likely chance of remaining in a happy marriage - if they even got married at all.

"What happens in Vegas - everything you do before settling down in marriage - may not stay there," Rhoades and Stanley continued, saying that "those who have had more romantic experiences are more likely to have lower-quality marriages than those with a less complicated romantic history."

About 90 percent of Americans have sex before marriage and on average, these Americans will have five sexual partners before settling down with "the one."

The study pointed to the probability that the more familiarity one has with relationships and sex, the harder it is to maintain commitment to just one person and to continue their satisfaction with only one partner. Marriage involves leaving behind other options, which may be harder for people who are used to having their choice of multiple romantic partners.

Having multiple relationship experiences also alludes to the conclusion of having multiple break-ups, leading to a more skewed viewpoint of lasting love and committed relation.

The same goes for cohabitation. Most American couples think that moving in together will help make the transition into marriage smoother. However, cohabitation before marriage has repeatedly been associated with higher divorce rates over the years, according to the study.

Stanley and Rhoades pointed out that cohabitation, which includes creating a life together - buying furniture, investing in a pet, paying monthly rent together - can create a kind of inertia that makes it harder for the couple to breakup, if the time came.

So instead of breaking up if the match proved to be unsuitable, the couple would likely stay together in a kind of unhealthy paralysis. The cohabitating couple would more likely enter into an unhappy marriage rather than delve into the inconvenience of breaking apart the life they so carefully created when living together.

Therefore, the findings of Rhoades and Stanley seem to show that in the case of marriage, having more sexual experience leads to a lower marital quality.

Marital quality in this particular study was defined by happiness, confiding in one another, believing things in the relationship were going well, and an absence of thoughts of divorce.

"In general, couples who wait to have sex later in their relationship report higher levels of marital quality," Rhoades and Stanley continued, pointing to the fact that sex in a relationship - especially hooking up early on - will have repercussions on marriage.

This could have to do with the fact that typically, both parties are be blinded by attraction. The couple who has sex early on in the relationship still has no idea if they are well-matched because they are captivated by sexual enthrallment. If the relationship starts off with sex, then the more detailed and subtle aspects of their partner could be glossed over by the hazy lenses of sexual attraction.

The research also suggests that if an individual only has sex with their eventual spouse and no others, the odds of marital happiness are substantially better than if the individual had sex with multiple partners.

However, marriages are not fated to end in divorce when their past involves messy break-ups and haunting hook-ups - there are ways to maneuver this new, uncharted phenomenon.

"The more support a couple has, the better they are able to navigate the occasional choppy waters associated with marriage," Rhoades and Stanely found.

One of the most interesting revelations of the study was that those couples who had more guests at their wedding reported greater marital quality, alluding to the possibility that commitment is strengthened when publicly declared, symbolizing a clear decision to commit.

This not only highlights the significance of community, family, and friends in a relationship but also suggests that community and a circle of support is one of the many ways that couples can enhance their chances at a happy marriage and renew their desire for committment.

In addition, the professors added that seeking advice, couple counseling or therapy, and transparency about past relationships could also be helpful for those want to escape the wounds inflicted by the casual sexual habits of the past.

"Our bottom-line advice to Americans hoping to marry is this: Remember that what you do before you say 'I do' seems to have a notable impact on your marital future. So, decide wisely."