Nagging. Discuss.

"Honey, don't leave those dishes in the sink."

It starts as an innocent reminder. You think you're just being helpful. You think there's nothing wrong with your tone. But somehow, when you utter the line for the 10th time, your relationship explodes.

Sound silly? Think again.

This Wall Street Journal column calls nagging a "marriage killer." An excerpt:

Nagging can become a prime contributor to divorce when couples start fighting about the nagging rather than talking about the issue at the root of the nagging, says Howard Markman, professor of psychology at the University of Denver and co-director of the Center for Marital and Family Studies.

For 30 years, Dr. Markman has researched conflict and communication in relationships and offered relationship counseling and marriage seminars.

He says that while all couples deal with nagging at some point, those who learn to reduce this type of negative communication will substantially increase their odds of staying together and keeping love alive. Couples who don't learn often fall out of love and split up.

The next logical question: When does necessary communication become nagging?