Dr. Laura,
My parents always emphasized to me that marriage is a two way street and it takes a lot of dedication to make things work. They also taught me the importance of communication and expressing your expectations to each other. When you know what the other person expects, it makes the relationship easier. We can't read each other's mind.
One piece of advice I keep close to me is, that you have to give in sometimes and pick your battles. It's like rocks rubbing together. In time the sharp points wear off and the rocks become smooth, easily fitting with one another. To be in a successful relationship means learning how to unite with each other.
