John Gottman says, in his book The Marriage Clinic, that there are basically two things that make the difference between couples who stay together and those who do not. First is what he calls the partners’ “uninfluenced stable steady states,” which are a result of the temperament of each partner plus the history of the relationship.  The second is the partners’ “influenced stable steady state,” which is the emotional direction that each partner takes, once they are interacting.

If the way you feel and act worsens when interacting with your partner–that is, if your influenced steady state is more negative than your uninfluenced steady state–you may well be heading for a divorce. The crucial question is, how much negativity from your partner does it take to turn your mood negative? If you can respond in a positive way to your partner, regardless of their mood or complaint, that’s a real strength. If you respond in a negative way, this is trouble. Negativity will tend to escalate in each conversation and throughout your relationship. Gottman says that if you cannot maintain a ratio of 5 to 1 positive-to-negative interactions at worst (that is, during conflict) you are heading towards (or are in) an unhappy relationship. If you dip below a 1 to 1 ratio, you are heading toward divorce.

“Negative affect reciprocity” is a closely-related pattern that Gottman says is the best predictor of happy or unhappy couples. (“Affect,” remember, is just a science-y word for emotion.) The extent to which you are more likely than usual to be negative when your partner is negative (as opposed to when your partner is neutral or positive), you are showing negative affect reciprocity. This could look a lot of ways, like responding to anger with your own anger, responding to criticism with stonewalling or defensiveness, responding to sadness with irritation, and so on.

Gottman says that negative interactions are inevitable, so what he calls “successful repair attempts” are all-important. That is, emotional repairs such as humor, taking responsibility, compromise, and soothing, must be offered, recognized, and accepted. When couples can recognize and accept all of each other’s repair attempts, he says, they are finished with therapy.