At the statistical intersection where increased life expectancy balances out the divorce rate, there is a surprising new cultural demographic: More Americans are reaching and exceeding the 40th wedding anniversary.

What's keeping more married couples together? Todd Migliaccio, a Sacramento (Calif.) State associate professor of sociology, is working to figure that out in a interviews with couples married 30 years or longer, or with a surviving spouse.

"We tend to focus on the fact that more people get divorced now," said Migliaccio, 37. "But maybe we should focus on the increasing number who stay married longer."

It's a sunnier approach, after all. There's only so much the group most at risk of divorce - newlyweds married five years or less - have to share with the world.

On the other hand, couples who have stuck it out through thick and thin might have a few things to teach us.

So far, Migliaccio has interviewed six couples, some of whom he found after posting a request for volunteers at Sacramento's Hart Senior Center. His plan was to videotape them talking about their marriages as a way to sweeten the dose of reality he provides students in class.

"We have certain expectations of marriage and family that often can't be fulfilled," Migliaccio added. "This is about going in with a realistic viewpoint."

Compare that with the pop-culture focus on brides, wedding dresses and ridiculously expensive weddings, which all but ignores the fact that after the wedding comes the marriage.

So has he discovered any secrets to long marriage yet?

Communication, respect and shared interests are among the themes emerging from his interviews , says Migliaccio.

"These are not check boxes," he said. "You develop a communication style and openness, and from that comes common interests and respect for the individual. I'm trying to get my students to stop looking for check boxes and the ideal picture."

He also wants his students to learn that every marriage faces difficulties.

"The key is how you overcome obstacles," he said. "Every marriage that's together 40 years is not perfect all the time ... Just because it's hard doesn't mean it's bad. It means you're working through something you're committed to."