By Oliver Jones
September 07, 2009 12:00 PM

For David Duchovny and Téa Leoni, it’s been a summer worthy of a special chapter in the family album. On July 24 they took the kids Madelaine West, 10, and Kyd Miller, 7, to Cirque du Soleil’s Las Vegas show Love. Then they all hopped in an RV and headed out on a cross-country odyssey, popping into a candy shop in Flagstaff, Ariz., catching a baseball game in St. Louis, touring Amish country in Ohio and finally stopping for a breather in South Dartmouth, Mass., the seaside town where Leoni’s parents have a home and where she spent her summers as a little girl. There the couple had some quality time to themselves—and made the most of it, slipping out to a showing of The Hangover and a romantic dinner. “They were constantly kissing,” said an observer of the couple, who dined together at the Black Bass Grille on Aug. 2. “They seemed really happy.”

The most surprising thing about the trip? That it happened at all. A year ago, the now 12-year marriage between the onetime X-Files star, 49, and the acclaimed actress, 43, appeared to be in tatters. In August 2008, Duchovny stunned both friends and fans when he announced that he was entering rehab for sex addiction. Shortly after he completed his treatment in October, the couple announced that they had been separated for months.

Then, gradually, they began to reappear. The couple, who first met early in their careers when they were both interviewing for the same guest spot on The Tonight Show, were seen in October strolling at a Manhattan street festival and taking in a Knicks game with the kids in December. But at the time, friends insisted it was too soon to declare a reconciliation. “They remain incredibly close,” a source told PEOPLE. “Their first priority through everything was staying close for their kids.”

Nominated for a Golden Globe for his Showtime series Californication, Duchovny walked the red carpet solo in January, telling reporters Téa and the kids were at home. “There’s a lot of love in our family,” the Princeton grad told Access Hollywood. “Last year was a difficult year. And I personally have never felt better, and I think the better I am the better my family can be.”

By summer the once estranged spouses were acting more like newlyweds. They spent Father’s Day frolicking on the beach in Malibu, and when Leoni came as Duchovny’s date to the July wrap party for Californication, they only had eyes for each other. “David and Téa came in holding hands,” says a guest. “They stayed pretty cozy the rest of the night.” Soon Duchovny, who once said he didn’t like wearing a wedding ring that he might end up losing (instead, on their 10th wedding anniversary, he chose to signify his marriage with a tattoo on his ring finger), started to be seen around town sporting a wedding band.

So what turned things around? Friends credit Duchovny’s rehab, which one notes that he did in large part to save his marriage. “David is in a really good head space right now,” says a pal.

Duchovny and Leoni’s reps won’t comment on the status of their relationship. But what is clear to both friends and those who spotted them on their cross-country adventure this summer is that the couple, who always had an uncanny ability to make each other laugh, have been doing a lot of that lately. “They seem to really be enjoying each other’s company these days,” said a source close to the couple. “It’s a great thing to witness.”