It’s common to observe that weddings are becoming more and more expensive. The downsides to this trend are plentiful and concerning, because this trend may place marriage even further out of reach for many couples as long as there is public pressure to spend so much. I think there is a reason for trend, and it lies in a theory about why a more expensive wedding with more guests could make for a stronger marriage for some couples.

How could this be the case? These days, most people still want to get married, but an increasing number feel unsure about marriage and their likelihood of achieving a happy one. Such mixed feelings produce all sorts of behaviors aimed at accomplishing that goal while trying to lower risks (like cohabiting before even getting engaged, much less getting married, which can be counterproductive to a strong foundation in marriage). The pressure for ever larger and more expensive weddings may also be based in a mechanism to strengthen marriages that impacts people even if they are unable to articulate it.

Here’s how that could work. For understanding this, I turn to something called consistency theory. According to the work of psychologist Charles Kiesler and others, individuals want to maintain consistency between their thoughts and actions, and they seek to reduce inconsistencies in their lives by bringing their present attitudes and behavior in line with their past behavior. So someone who at one time believes that voting is a civic duty, but then fails to vote in several consecutive elections, may amend their views about voting to be more compatible with their behavior. Conversely, someone who has taken a strong, public stand in favor of recycling will feel more internal pressure to behave in accord with that public stand, with their behavior falling into line over time. People are often inconsistent, of course, but there is a press within most of us to keep it all consistent.

If you spend a lot on a wedding and say your vows in front of a crowd, you’ll feel more internal pressure to follow through on the marriage.

Expanding on consistency theory, Paul Rosenblatt theorized in the 1970s that early in a marriage, marital stability and commitment will be positively associated with the ceremonial effort and public nature of a couple’s wedding. After a big wedding, the couple feels accountable to many observers. In fact, Rosenblatt suggested that a large, public wedding would lead a person to conclude, internally, that he or she must have been really sincere in the commitment to have taken vows in front of so many people. Similarly, those who have invested a great deal of any resource (time, effort, money) into a relationship will tend to bring their attitudes in line with their committing behaviors.

Consistency theory could be one factor behind what we now see: the trend toward lavish wedding spectacles. Everything done perfectly and in front of many witnesses. What does an expensive wedding buy a couple? Rosenblatt’s prediction from decades ago is right in front of us. If you spend that much and make this statement in front of that many people, you must really mean it. Right? You’ll feel a lot of internal pressure to follow through—and thus, when you and your spouse have your first big fight, you’re a bit more motivated to work things out and keep the marriage strong.

In a culture where marriage is increasingly popular among the affluent relative to other groups, yet it remains something people feel anxious about, this trend toward bigger and more audacious weddings will likely continue. It’s as if people are attempting to buy one more type of insurance for their marriage. This standard has many unfortunate downsides: It puts a financial strain on couples at an already stressful time, and causes many to delay the ceremony against their wishes. Moreover, it places the bar ever higher for those who feel especially vulnerable about marriage working out—those who have very little resources.

Most importantly, buying a wedding and buying into one’s marriage are two different things. The former might help some couples a little—but the latter is essential for all couples who are going to make it.