It's easier to maintain a fire than it is to reignite a spark!
The mistake a lot of couples make is downplaying the importance of sex and romance in marriage.
Usually if there is no sex in a marriage then there usually are no wet kisses, hand holding, snuggling, listening intently to one another, taking showers together, hugging,,,etc
Before there is a physical disconnection there is a mental disconnection. The only way to start to become emotionally connected again BOTH people have to first acknowledge they're unhappy with the way things are and decide together to put more effort into improving things between them.
No one person can save a relationship or put the spark back into one.