Is your relationship stuck in a rut?  If you’ve got taco night, movie night and game night on a regular rotation, that comfortable routine could be toxic.

In this study, 123 married couples completed surveys measuring their level of excitement, marital satisfaction and closeness after seven and 16 years of marriage.

Not surprisingly, couples that were bored in year seven were less satisfied in year 16. But the reason for the downturn might surprise you.

Results showed that boredom undermined closeness, causing couples to grow apart. That pitter-pat of the “getting-to-know-you” phase comes from a rush of dopamine, a chemical in your brain that is stimulated by novel activities.

Years into marriage, when you know your partner all too well, seeking out excitement can reignite that early flame and bring a couple back together. Skydiving, anyone?