Let the Fire Light Itself
Allow your marriage to become another routine that you live each day-to-day - not if you want to stay happily married. The fire is not going to light itself, you have to make the effort and start the flames. Every marriage needs some level of spontaneity. Never letting the flame die is one of the essential keys to having a long lasting marriage. Keep things alive and aim to surprise each other. It doesn't have to be extravagant. It can be as simple as cooking dinner, if you do not normally cook or surprising your spouse with a date night.