I will look and take from my brother, who is 25 with a 21-year old wife, married for 3 years, and currently have a 3-month-old daughter.
What my brother has told me is that marriage requires a lot of compromise. Not that often do you get exactly what you want, and you'll often have to settle for something that you both or only one agrees on. I see that they often argue and tease each other, and then have romantic moments in front of me (Do not want), but he also told me this.
"Marriage means that you both trust each other and care for each other. If my car broke down in the highway at 4 A.M., I trust that my wife will come and get me no matter what. Similarly, if her car brakes down in the highway at 4 A.M., I'm getting up and getting her."
I guess the point of this quote is that from what I know, marriage means that you love each other enough to make it through a few hard times and help the other when one is down. Aren't the wedding vows "for better or worse, for richer or poorer, in sickness and in health"? This is coming from someone who has never even gone on a date (damn my nerdy ways), but I suppose most people aren't willing to stick it out when they realize marriage isn't just being together with your love. It means making sacrifices to make them happy, and them doing the same.
When my sister-in-law had to be admitted into a mental hospital, my brother made the hour-long trip every day to see her so she wouldn't be alone. I remember how worried she was when my brother had appendicitis, and went into surgery. He does the chores she doesn't like, and she does the chores he doesn't like. I guess not that many people these days are willing do work things out when things don't seem great anymore. Instead of dealing with the stress and demands of marriage, most people would rather end it and look for someone else. I don't think there's a such thing as a "perfect" marriage. But if you want it to be close, you have to make a few compromises, communicate, and see if you can find a way to make it work. Instead of shoving the round block into the triangle hole, work it out until it goes in the circular hole.
Yes, I know that last metaphor was stupid. Sorry for the text wall.