I think it has a lot more to do with the way media portrays love and the ease of getting a marriage license. When you have people convinced that the fluttery, nervous feeling they get in their stomach is true love as opposed to the normal "sparkle" stage of any relationship, they can be led to make some stupid decisions. If you had to complete a 3-6 month relationship counseling class before you could legally get married, that might also give people more insight into how to negotiate in a relationship, what needs to be there for it to work, and if there are any big things to consider before they get married. Then, once married, I don't think most people are well-equipped to figure out how to disagree with a partner and how to resolve conflict. A lot of people seem to think that conflict in a relationship is abnormal and a sign that you can't be together anymore. So, I think it's more about unrealistic expectations fed by popular media and less of the practice of two people deciding to be monogamous for a while.