Nagging is as toxic as adultery say experts.

Nagging—the interaction in which one person repeatedly makes a request, the other person repeatedly ignores it and both become increasingly annoyed—is an issue every couple will grapple with at some point. While the word itself can provoke chuckles and eye-rolling, the dynamic can potentially be as dangerous to a marriage as adultery or bad finances. Experts say it is exactly the type of toxic communication that can eventually sink a relationship.

Why do we nag? "We have a perception that we won't get what we want from the other person, so we feel we need to keep asking in order to get it," says Scott Wetzler, a psychologist and vice chairman of the Department of Psychiatry and Behavioral Sciences at Montefiore Medical Center in New York. It is a vicious circle: The naggee tires of the badgering and starts to withhold, which makes the nagger nag more.

It is possible for husbands to nag, and wives to resent them for nagging. But women are more likely to nag, experts say, largely because they are conditioned to feel more responsible for managing home and family life. And they tend to be more sensitive to early signs of problems in a relationship. When women ask for something and don't get a response, they are quicker to realize something is wrong. The problem is that by asking repeatedly, they make things worse.