Rekindling romance with an ex may lead to stress and unhappiness.

That’s the finding of a Kansas State University researcher. Assistant professor Amber Vennum found that with college-age students, about 40% are currently in cyclical relationships – the term used for couples who break up and then get back together.

Vennum found that couples in a cyclical relationship tended to be more impulsive than other couples about decisions such as moving in together or having a child together.

As a result, these cyclical couples tended to be less satisfied with their partner; had worse communication; made more decisions that negatively affected the relationship; had lower self-esteem; and had a higher uncertainty about their future together.

Vennum has advice for couples who have broken up: “Don’t get back together.”