Why do some couples divorce after a short marriage?

There are many theories about why marriages break up, and for any given marriage any one theory may be correct. Some studies seem to indicate that some couples miss the feeling of being "in love." They entered the marriage deeply in love or one would hope and expected to retain those same feelings for the entire marriage. Most likely, daily exposure to one another dims the glow associated with being "in love," and marriages that last therefore evolve beyond it.

Perhaps, the dirty-and-sweaty-underwear-on-the-bedroom-floor theory explains why the intoxication of feeling in love gives way to other emotions.
Alas, even under the best conditions, daily living generates acids that work toward dissolving romance, which in the long run is not sturdy enough bedrock anyway. Moreover, personal eccentricities that seemed so charming when a couple is dating can, with time, become positively maddening. Spouses sometimes tire of one another.

After a time, a few months or a few years, however, they probably no longer feel the same way and therefore believe that the marriage is doomed. While they may no longer be "in love," they probably still love one another, but in a new and different way. If the couple can get past this period and adapt, essentially, to these new feelings, the marriage is likely to endure.

Sometimes people marry on an impulse, and realize almost immediately that they have made an egregious blunder. Sometimes people decide to marry and as they approach the wedding date one or both realizes that they are making a mistake, but the idea of the marriage has achieved momentum.