When in Rome

It was day four of a two-week vacation in Berkeley, California. Jason wanted to visit a famed vegetable market, but I found it so chaotic, I simply bolted after 20 minutes. He dutifully followed, then fumed for the rest of the afternoon that I had ruined the one experience he'd most looked forward to. I countered that I couldn't believe he would want me to stay in the middle of such mayhem if it made me crazy. It took hours before we could speak civilly, and the time in between was very, very quiet.

You've seen couples in this state before, those silent duos in restaurants, noiselessly picking at their food and avoiding eye contact. Nosy Nellie that I am, whenever I spot such sour pairs, I try to diagnose the problem. Bad first date? Night before one asks for a divorce? Affair gone awry? But when I see couples battling lockjaw in even the most idyllic vacation settings, the prognosis is perfectly clear: Fourth Day Syndrome.

The first day of any vacation is about process - catching your flight, checking in to your hotel, then ritually gushing, "We're really here!" On the second day, you're still flying high enough that it's easy to agree what to do with your time. But on day three, you are hit by the reality of balancing two agendas. Your spouse wants to see where his favorite foreign beer is bottled, while you want to find a beach. Aiming for compromise, you unwisely squeeze in both events and wind up drinking warm beer before hitting the sand at the hot-test time of the day.

Day four is the day you've been together too long. You bicker over directions, nearly come to blows while trying to choose a museum, and find yourselves on the brink of tears when you go over dinner options. Sitting in a restaurant neither of you would have picked, you have to bite your lip to keep from saying ungenerous things like "I want to stab you in the forehead with my salad fork," and remain painfully silent while time slows to a crawl.

Since our Berkeley vacation came after just 10 months of dating, it was fairly early in our relationship when we figured out that splitting up may well be the key to staying together. Since that market-day meltdown, we've practiced the four-day rule on our vacations, spending time apart at least every fourth day. Instead of trying to sell the other on every activity that appeals to each of us, we share only those things that truly appeal to both while making time for solo excursions that satisfy our individual interests.

Why drag your partner along on an ocean snorkeling excursion if the only place he likes seeing fish is on the specials board of a restaurant? Why ruin your sweetie's delight in a narrated trolley tour by pointing out that he might as well wear a fanny pack and a T-shirt bedazzled with the word "TOURIST"? Just go your separate ways for the day, have the experiences you want, and reap the rewards at dinner. At the end of your fourth day, instead of silently fuming, you'll both have your own fresh stories to tell.

After we celebrated our 10th wedding anniversary by getting legally married last year, we honeymooned in Paris; even in that epicenter of romance, we knew better than to push it. We didn't even bother to wait. On the third day, Jason went to a cookware outlet - the thought of which makes me yawn - while I sat writing in a cafe, something too sedentary for him. That night, over plates of gooey cheese, each of us saw how happy our respective days had made the other. He'd found the stockpot of his dreams, and I had a new scene for a play. Two days later, we set off on our own again, with similarly pleasing results.

Here's the secret: The days between were even better. Agreed-upon time apart recharged our personal batteries, and we got back together ready to focus our renewed energy on being a couple. Together, we wandered through cobbled streets, admired art, made love, and ate way too much. In fact, there was never a meal on that trip when a casual observer would have thought, "Poor guys must be breaking up." For in that entire week, the fourth day never came.

David Valdes Greenwood lives in Arlington. E-mail comments to coupling@globe.com.