Kids do what they see us do
Although this applies particularly to young parents and young children, it is true of older ones as well. We will be parents all the rest of our lives, from the moment of conception.
How we love our spouses is the most important example we can give our kids. If the two parents are the most important humans in each other's lives, the children win, because there is more than enough life to go around. If the parent's make the children more important than their own relationship, everybody loses because the example given will remain in their training for the rest of their lives.
Example Over Advice - Fallible Blogma