The Sex Hormone, Love and Marriage: A Theology of the Body Reflection

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I just read a study that started by saying, “Pre-marital sex predicts divorce, but we do not know why.”

The study found that the odds of divorce for these couples are double to triple — increasing as the number of sexual partners increases — over those who saved sex for marriage. These results remained consistent even after adjusting for religiosity, beliefs and values. In other words, it isn’t just because the “savers” are religious and hence don’t believe in divorce. Nor did they find any gender differences.

The study definitively establishes that yes, premarital sex is a “highly significant predictor of divorce.” But what they couldn’t figure out is “why.”

I may have some thoughts on that subject.

Do you remember several months ago, when we talked about the hormone oxytocin? It is secreted in huge amounts during sexual activity. It has been called the “monogamy molecule,” the “love hormone” and the “superglue of the heart.” Its impact, among other things, is to decrease our ability to think rationally and to cause a strong emotional attachment with the person we’re with.

In other words, sex is not just something we do with our bodies while we check our brains out at the door. It is emotionally and spiritually powerful. It finds two people in one of the most intimate, vulnerable situations they can be in, and it chemically binds them together.

I wrote at that time about how lovely this is for spouses — how beautiful it is that God built that powerful bond right into their self-gift, how it strengthens their relationship and enhances their marriage.

But what happens when we take that bond out of the context of marriage?

Back when I was speaking to teenagers, I used to say that dating is “interviewing for the job of spouse.” The purpose of dating is supposed to be to figure out a) if you want to get married, and b) if so, to whom. It’s about getting to know a person on a deep level, to figure out if this could be the person you want to spend the rest of your life with. Apart from the decision to follow Jesus Christ, this is probably the single most important decision most people will make. Certainly, it’s a decision that has a profound impact on the rest of their lives.

So what do these two people need more than anything? Objectivity. A clear mind. Rationality. Discernment.

So how much sense does it make, in the context of such a life-altering decision, to give up that objectivity? To allow this overwhelming bonding process to blur our vision, to chemically unite ourselves to the very person we are evaluating?      

In the early stages of any relationship, we need to be asking, “Who is this person? What is his character? Is she capable of selflessness? Does he treat me well, look out for what is best for me? Do our values align?” But once that bond is formed, it is easy to slip into irrationality, with those questions taking a back seat to “I need to make this relationship work.”

To me, it looks like the worst possible way to make a lifetime decision of the magnitude of marriage.

So what does all of this have to do with divorce? Well, first of all, the intensity of the bond can mimic the intensity of being “in love,” while simultaneously obscuring the red flags that indicate incompatibility or downright disaster. Let me say that again: the bond formed by sexual activity blinds us to relationship red flags. “I need to get out of this” morphs into “but I love her” or “I’ll change him.” The decision to marry is based on the hazy high of the bond, and not on the full reality of the other person. But of course, that chemical bond alone is not enough to overcome infidelity, abuse, garden-variety incompatibility or whatever other problems emerge in the marriage that would have been evident if clearer minds had prevailed. And so the marriage often fails.

But why does the divorce rate increase with the number of premarital partners? The impact of oxytocin lessens as the number of sexual partners increases, and repeated, non-exclusive mating leads to less effective exclusive, long-term pair bonds. In other words, sleeping with multiple partners burns out our ability to bond.

If the ability to bond is impaired, it could make people more objective when evaluating a partner. But the trade-off is that, even among the most compatible couples, a lifetime commitment is daunting, and they’re going to need some help living it out. Which, I believe, is why God gave us this beautiful gift of bonding in the first place. Without that help, I imagine it would be much more difficult to stick with a marriage through the inevitable challenges.

Please remember that these are risks, not destiny. Your mileage may vary. I have known plenty of successful marriages where sex predated the ceremony. But, having come of age amid a group of truly faithful Catholics, I have also seen plenty of couples who waited. And I have to say, there is something special about those unions. You can see it in the way they interact, the way they are together. Sure, marriage is difficult, and they face their share of challenges. But even during whatever difficulties, there is something solid, something beautiful shining through.

So what do you say to people who have never heard this, who made mistakes because they didn’t know any better? How, in this culture, would they know?

We can never discount the action of the Holy Spirit. The past doesn’t have to be a blueprint for the future. Our God is a God of restoration.

I would very much like to see a “Mary Magdalen” study. Somebody needs to study couples where one or both, after a promiscuous past, had a conversion experience followed by a chaste courtship and sacramental marriage. Or couples who together find faith after they have been married. I would bet on those marriages to go the distance.

God invented sex. And he invented marriage. His Church has always said that they work best together.

The longer I live, and the more I learn, the truer I find that to be.

The study referenced in this column is Smith J, Wolfinger NH. Re-Examining the Link Between Premarital Sex and Divorce. J Fam Issues. 2024 Mar;45(3):674-696.