Today, most women are surrounded by ingenious gadgets. They don't grow the peas or raise the chicken that they serve for dinner; instead they hunt and gather in the grocery store. They go through catalogs or department stores to buy clothes instead of shearing sheep, carding wool, and weaving cloth for skirts and coats and blankets.

Games are the way we keep romance alive. They're based in human hardwiring. Playing hard-to-get or leaving a little to the imagination allows the woman to be wooed and appreciated and the man to be challenged and intrigued.

We all have restlessness in long-term relationships.

Research shows that couples who have a lot of similarities, including intellectual compatibility, end up staying together.

Both sexes like the exercise and challenge of sports, but for men it's also a basic display behavior for impressing and winning a mate.

In America, we are demanding everything from our marriage.

Men tend to be hierarchical, but women are driven to make lateral connections so they can cooperate.