A lasting marriage does not always signal a happy marriage. Plenty of miserable couples have stayed together for children, religion or other practical reasons.

But for many couples, it’s just not enough to stay together. They want a relationship that is meaningful and satisfying. In short, they want a sustainable marriage.

“The things that make a marriage last have more to do with communication skills, mental health, social support, stress — those are the things that allow it to last or not,” says Arthur Aron, a psychology professor who directs the Interpersonal Relationships Laboratory at the State University of New York at Stony Brook. “But those things don’t necessarily make it meaningful or enjoyable or sustaining to the individual.”

The notion that the best marriages are those that bring satisfaction to the individual may seem counterintuitive. After all, isn’t marriage supposed to be about putting the relationship first?