With only weeks to go before their wedding, Trista Rehn, 31, and her Bachelorette fiancé, Colorado firefighter Ryan Sutter, 29, have moved into a four-bedroom home near Vail. Outside the air is crisp and scented with pine. Inside it's all dog, all the time, and Rehn keeps breaking out in hives. She's acutely allergic to Natasha, Sutter's 5-year-old Siberian husky. "For the past two weeks I've had huge welts on my face," says Rehn, a former physical therapist who grew up in St. Louis, "because I'll lean up against Ryan's shirt where Natasha has touched him." Can this relationship be saved? Yes, but at a cost: Rehn is off to see the allergist. "I hate needles, but I'll deal with it."

That sort of thing – those little day-to-day signs of commitment – make Sutter very happy. "It makes me feel good," he says. "That's part of a relationship – you do things maybe you wouldn't have before."

In fact, the couple will soon be making reality-romance history. Not only will they be the first Bachelor sweethearts to actually tie the knot, but their nuptials will be taped and then aired on ABC Dec. 10. The two-hour wedding extravaganza will cap a three-part series of specials that promises a Harlequin romance wrap-up to the story that began when Rehn was rejected by Alex Michel on the first Bachelor in 2002, then fell for Sutter when she got to star on the Bachelorette this past winter. Cynics might point out that bride and groom are contracted with the producers to receive a total $1 million by the time they successfully finish exchanging their I dos. Says Rehn: "If you don't want to believe in us, that's okay. We're still going to be in love."

And at least until the wedding, she's going to be very much in charge. With an enormous production budget, she's putting together the ceremony of her dreams with some of the big names in the bridal business. "Trista's very much into the romance of a fairy-tale wedding," says florist Mark Held, who worked on the yet-to-be-completed Ben-Jennifer wedding. But she always consults Sutter and has given him the deciding vote on the cake. "So as long as there are sweets," says wedding planner Mindy Weiss, who oversaw the Jessica Simpson-Nick Lachey wedding last year, "Ryan'll be happy." And probably grateful: "When we first did the guest list," he says, "it was a little overwhelming."

But Sutter's learning. And so is she, as daily life reveals more details about each other's off-camera self. "He's very neat about his appliance cords," says Rehn, who envisions having kids and commuting to L.A. for TV work. "We have iPods, and he'll wrap the cord perfectly." A seafood- lover, he wishes her diet wasn't so heavy on starch. "It's hard for me to emphasize how big she is on potatoes." But when they wake up each morning, usually by 9:30 – she never used to get up before 10 – they're thrilled to face another day together. "In the morning," says Sutter, "I call her Sunshine."