In the book of Revelation, we read about the four horsemen of the apocalypse. I believe that there are four horsemen of the apocalypse that relate to marriage:
Sin Romance dies when one or both persons become so wounded or disillusioned with a spouse that they become calloused. Sins and harsh actions are unrepented of until the wounds of sin have removed all feeling. "A brother offended is harded to win than a strong city, and contentions are like the bars of a castle" (Proverbs 18:19).
Age
Romance dies when a person focuses on the outer beauty rather than on the inner beauty of his or her spouse. Outer beauty degenerates over time; age takes its toll on every person. I don't care how many face or body lifts a person has, or how much a person attempts to keep in shape through proper nutrition and exercise, age causes a fading of physical beauty. Unless you continue to see beyond the wrinkles around your beloved's eyes and gaze into the full depths of your mate's soul, you will feel less attracted to your spouse, and with a lessening of attraction, you are likely to express less romance.
Forgetfulness Romance dies when couples forget the preciousness of their mates. Spouses too often come to take each other for granted, and they lose sight of just how special they are to each other. Romance requires intention, care, and focus. It requires that each person keep in active memory what gave birth to their marriage. It requires that each person continue to remember the special traits in the spouse that fueled attraction at the initial stages of their relationship. God calls a man's bride "the wife of your youth" (Mal. 2:14).
Laziness
Many people recite vows to "love, honor, and cherish" a spouse, and then they proceed with their marriage without a good knowledge of how to keep them. Love must be shown. Honor must be expressed. Cherish is an attitude that must be displayed. Passionate marriages are so by design and intent. Romance is a discipline.
Content taken directly from The Book of Romance by Tommy Nelson, published by Thomas Nelson Publishing, copyright 1998.