Drawing on extensive surveys of couples, "The Normal Bar" explores what couples do to keep their relationships strong. — Getty Images

What is considered normal when it comes to sexual relationships these days? That's what Pepper Schwartz set out to discover as she researched her new book, The Normal Bar: The Surprising Secrets of Happy Couples and What They Reveal About Creating a New Normal in Your Relationship.

"I think of it as everybody has their way of doing life," says Schwartz, AARP's relationships expert, who wrote the book with coauthors Chrisanna Northrup and James Witte. "That's your normal. But which normal seems to be correlated with a happy couple? What makes for happiness?"

AARP Radio host Mike Cuthbert talks with Schwartz about the ever-changing parameters of normal and how happy couples find the status quo that fits them best.