Here is an excerpt from one article:
Reasons not to fornicate, besides "God said so"
orthodoxwriter.com/2012/03/reasons-not-to-fornicate-besides-god.html
The ultimate “expert” on any subject is, of course, God—but here are ten expert recommendations from the secular world against sleeping/living together before marriage. In one way or another, they all echo the Lord’s commandment.
1. It leads to an increased rate of infidelity.
Both partners need to learn how to control their urges and impulses before marriage. If one or both of you can’t keep your hands off of the other now, a wedding isn’t magically going to teach you how to keep them off of other people in the future. Research on thousands of men across multiple countries confirms this:
More sex during dating means more infidelity during marriage.
2. It leads to an increased rate of divorce.
If you sleep with someone you don’t end up marrying, your
risk of divorce will be significantly higher once you do get married. In a study of 6,500 married women, the divorce rate was three times higher for those who’d had multiple sexual partners than for those who were never intimate with anyone other than their husbands.
3. It leads to decreased sexual satisfaction in marriage.
People tend to think you have to “practice” physical intimacy before marriage in order to get the most out of it during marriage. One of the most liberal studies ever conducted, however, revealed the opposite:
People who were completely abstinent prior to marriage are more satisfied during marriage, particularly those who abstained for religious reasons.
4. It leads to decreased feelings of romance.
Sexual experience with a partner you don’t end up staying with leads to a lessened experience of romance with whomever you do end up with. There’s a direct relationship between the number of your past partners and your feelings of romance with your current partner:
The higher the number of partners, the lower the feelings of romance.
5. It leads to less love and overall satisfaction in marriage.
Decreases in romance and sexual satisfaction aren’t the only consequences of out-of-wedlock sexual experiences.
Research confirms that the highest levels of love and overall satisfaction belong to people who (1) are married, (2) had the fewest number of sexual partners, and (3) did not live together with their current or any previous partners.
6. It leads to poor decision-making and partner-selection.
Sex outside of marriage is directly related to poor relationship choices.
Physical intimacy clouds good judgment. Several studies have shown that if you’re abstinent while dating, you’re likely to use better discretion in selecting a prospective partner. If you’re sexually active, however, you’re likely to overlook important aspects of a potential mate’s character, fidelity, and sexual history as long as you think that person is “sexy.”
7. Just because it’s great now doesn’t mean it will be great later.
Physical intimacy during dating isn’t representative of what it will be like during marriage, even if you marry the same person with whom you’ve been intimate. One researcher explains that this is because “the dating relationship has an agenda that marriage does not. … There is a lot of pressure to win over a partner, which causes a person to consciously or unconsciously please that partner in ways that may be very temporary.” He adds that the very reason a new relationship is so exciting is because of the tension of not having explored sexual intimacy with that person.
8. It creates unnecessary complications in the marriage bed.
There’s a learning curve with everything in life, including the physical aspects of a relationship.
When both spouses enter into a marriage inexperienced in that respect, they learn together, and a very special bond is created as a result. But when both spouses have learned things from being with other people—or worse, when one has and the other hasn’t—it gives rise to memories of past experiences, regrets about the ways in which one’s spouse might not measure up, and feelings of jealousy from the spouse.
9. It hides existing relationship problems and creates additional ones.
In marriage, sex can’t be separated from the other aspects of the relationship—the good and the bad. In dating, however, sex very often precedes the development of a solid relationship. Because of this, it can mask problems that exist but haven’t yet been identified by one or both partners. It can create temporary feelings of euphoria that will ultimately shatter, once those problems begin to surface. And if physical attraction happened to be the primary basis of the relationship, then there won’t be much left to salvage when that falls apart.
10. It can make a relationship very unstable.
According to one psychological model, there are five dimensions to any relationship: Knowledge, trust, reliance, commitment, and touch.
If the level of touch exceeds the level of anything else—if you don’t know everything you need to know about your partner; if you haven’t been together long enough to prove that this is someone you can trust; if you can’t or don’t know how to rely on him or her; and if there isn’t sufficient commitment (i.e., a marriage)—then the relationship becomes very unstable. It will leave you desiring all of the other aspects, but with no guarantee of ever receiving them.