Living happily ever after isn’t just for fairy tales! Researchers from Australian National University have identified what it takes to keep a couple together. And it turns out, it’s a lot more than just being in love.

The study is called “What’s Love Got to Do With It.” It tracked almost 2,500 couples over a period of seven years. Here are some of the findings: 

  • First: When one spouse is 9 or more years older than the other, the couple is twice as likely to get divorced. Ruth Houston is an infidelity expert and the author of Is He Cheating on You? And she says a large age difference may lead to infidelity because at some point there’ll be inconsistencies in the couple’s need for intimacy. 

  • Another factor is money. If couples were struggling to get by, or one of them was unemployed, they were more likely to separate. Financial problems put stress on a relationship.

  • And one more factor that determines whether a couple will split: When one partner smokes and the other doesn’t, the relationship is more likely to end in failure. Dr. Jerald Bachman is a scientist at the University of Michigan, and he’s found that smoking is a predictor of divorce, primarily because smoking is an addiction. Which means that the partner who smokes will have the bad habits and behaviors of an addict.

So what factors didn’t affect the risk of a break up? A difference in the spouses’ levels of education, and whether or not the wife worked outside the home. Neither of those had an effect on whether a couple stayed together.