By Katie Couric"Love is lovelier the second time around," Frank Sinatra once sang idealistically. (Never mind that second marriages have a higher divorce rate than first marriages-that's another column for another month.) My search for a second time around was born of tragedy. My husband, Jay, died in 1998 and I was a widow with two small children, trying to figure out the rest of our lives. Being without a partner was tough. I'm happiest in a relationship, and I don't love being alone. ...