Do we ever really know the people we marry? I wonder. Now, I've known my wife Fran for 15 wonderful years, 10 of them in the most beautiful, sharing, and trusting marriage anyone could ever want. But even after all these years, the new things I learn about Fran—with the help of private detective Barry Norman—continue to surprise and delight me.

For instance, every day on her way to work, Fran stops at Dunkin' Donuts to get a coffee. What an adorable little quirk—all the more so because the computer-simulated aerial map of Fran's route that Barry included in one of his weekly dossiers clearly shows that the doughnut shop is seven blocks out of her way. Cute, huh? Well, that's my girl! I wonder if Barry will ever truly document all her funny little ways.

Oddly enough, the receipts that she's tossed out the window—who knew that sweet little wife of mine would turn out to be a litterbug?—show that she has never purchased a single doughnut along with her coffee during three months of 24-hour surveillance. So why would a person go seven blocks out of her way just for coffee, when she doesn't even eat doughnuts? Just another of love's little unknowable puzzles that even the professional services of an ex-cop who charges $500 a day plus expenses can't explain.

Of course, even in a marriage as mutually loving as ours, there are little things you have to work on—but that's just part of what keeps the magic alive. Sometimes, Fran says that I don't listen to her enough, and having pored over the typewritten transcripts of all our conversations from the past three months, I admit I could improve in that area.

Sure, it's all "little things"—but it's those little things that make me fall in love with her all over again each morning. Take her vocabulary usage patterns: According to the old high-school report cards that Barry came across in Fran's parents' basement, Fran was never very good in English, but re-reading the text of our discussions from yesterday, I noticed she used the term "maladroit" in the correct context on three separate occasions.

Isn't that the most adorable thing you ever heard?

I would've thought that it was on some "word of the day" list, but Barry forwards me all Fran's e-mail, and yesterday was "circumambient." And I know for a fact, thanks to photos that Barry has secured, that she does not have one of those word-a-day calendars on her desk at work—she has a Far Side one. Who would have guessed that, after all this time, I'd still be able to uncover a quirky, loveable trait that bears further investigation. I should tell Barry about that.

It seems like ever since I hired Barry, I've seen Fran in a whole new light, and I don't mean the infrared he uses to photograph her while she's sleeping. For example, I never would have guessed that she gets up when I'm sleeping on as many as four occasions a night. That's the kind of thing that doesn't even cross your mind until a man with night-vision binoculars and a telescopic camera lens stations his van across the street from your bedroom window and monitors every moment of the cold, still night.

Isn't that the wonderful thing about love, though? The way there's always some new facet to uncover that you never knew before, little mannerisms they have that you never noticed—like the playful way that, in the footage from the super-miniaturized motion-sensor camera Barry installed in one of the bathroom tiles, Fran spins her tampons around on their little strings.

We've been married a long time, but I never get bored with Fran. I'll bet even after 10 more years, I could still stare at surreptitiously acquired video footage of her eyes for hours.