The idea that you need to work on your marriage every single day is a tough one for many people to understand. They often think that it should be easy and just come naturally, and that if they do need to work on it, then there must be something wrong with their marriage mate or with the entire concept in the first place. In reality, this is far from the truth.
Think of a good marriage as being like having a good career. There may be many things you do in your job or career that come easily and naturally, and certain tasks or requirements that aren't that difficult for you, but you probably work very hard every day to learn new things and to apply yourself to your job. Did you go to college or a trade school? Did you ever need to take evening classes to further your education, or sit through seminars that your employer offered? All of this means work and effort, and it's the same with marriage. You need to constantly be applying yourself, taking on new tasks, and learning new ways of doing things in order for it to work.
Your career has probably changed much over the years as well. Think back to when you started this particular job or line of work. Are you doing the exact same thing in the exact same way? Probably not. There are few careers and jobs that stay the same; even fast food preparation is always upgrading to new machines or procedures. Your marriage is much the same. It changes over the years as your life just naturally changes. Children arrive and then eventually move out, you may need to move yourself physically to a new city or state, and you face different problems over the years as well. Just as you've had to adapt to new circumstances in your career, you need to adapt to new circumstances in your marriage as well. This takes work and effort.
Adapting to your spouse takes work on the marriage as well. We all change over the years, especially as our bodies get older and we face new problems and our likes and dislikes and values change as well. Some think that a person should never change from the first day of marriage, but this too is unrealistic. That person who used to love going out and dancing until dawn may now find that he or she is tired after a long day at work and taking care of the children and prefers to stay in. Those friends that you used to find amusing now just annoy you as being childish and immature. Things you used to love doing together have now gotten boring. Working on a marriage means adapting to these changes in your spouse as well. This might include finding new things to do together, finding new friends you both enjoy being with, and adjusting our own preferences to accommodate him or her. Again, this all takes work, but of course it's worth it!