Go On A Date

Especially for married couples, but even for some "dating" couples, start dating.  Often people become very comfortable in their relationship and sitting around on the weekends, watching movies is about as exciting as it gets.  Ask your mate out.

For example, actually call them and ask, "if you do not have any plans for Saturday night, would you like to go to a concert with me?  It is crucial to relationships that they keep the fire alive by enjoying the act of dating.  There are many people in long-term, successful marriages that will tell you they go out on dates every week, which has been a huge bonus for their relationship.