By Joey Bartolomeo
September 13, 2010 12:00 PM

On their recent trip to Maui, three activities have dominated Britney Spears and Jason Trawick’s agenda: sunning, smooching and smiling. “They seem completely in love and happy,” an eyewitness says of the pair, who, it’s safe to say, have had marriage on their minds. On Aug. 26 they toured a wedding chapel at the Grand Wailea resort, and two days later they spent an hour watching a couple exchange vows on the lawn below their hotel room balcony. “Britney even teared up at one point,” says a witness. “She clapped and cheered on the newlyweds after they were pronounced husband and wife.”

Could Spears and Trawick be getting ideas? While it’s clear the couple of more than one year have moved beyond the troubles they had this spring, a close source insists they’re not heading down the aisle-yet. “He’s turning 39, and she’ll be 29 [in December], so of course they talk about the future and the possibilities,” says the source. “But they’re taking things day by day and really enjoying their time.”

Their relationship began to improve after Spears-whose kids, Preston, turning 5 Sept. 14, and Jayden, 4, spent time with their maternal grandparents in Los Angeles while Mom was away-“realized that Jason would disappear unless she started acting more mature,” says an insider. It’s also helped that Trawick, a Hollywood agent, stopped working with his girlfriend professionally. “He really cares for her, deeply cares for the kids and loves her family,” says the close source. And the feeling is mutual: “The boys,” says the insider, “love him very much.”

The vacation caps off a busy summer for Spears, who has been recording new music and recently filmed a guest spot on Glee. “She had a really good time on-set,” says a source. And the cast was thrilled to have her there. “She was super, super nice,” Kevin McHale, who plays Artie, tells PEOPLE. Adds Heather Morris (whose character, Brittany, channels Spears in the episode): “It was awesome.”

When Spears and Trawick return to the mainland, she’ll likely be wearing her vacation smile for the foreseeable future. “She’s enjoying things and just going with the flow,” says the close source. “Life is good.”