'Selling the OC' Star Alexandra Jarvis on Her 'Sexy' and 'Very Couture' Custom Wedding Dress (Exclusive)

Alexandra Jarvis had a clear vision of what she would wear on her big day.

The Selling the OC star, 32, tells PEOPLE that she "didn't want any traditional wedding dress" with all white heavy fabric as she married CEO Sergio Ducoulombier on Friday at the Villa del Balbianello, overlooking Italy's Lake Como.

"I know my body style. I also used to model wedding dresses growing up, and so I knew what I wanted, what I didn't want," explains Jarvis, adding: "I wanted something couture, sexy, but still elegant and feminine."

She says designer Michael Costello was very "hands-on" in bringing her vision to life with a "completely custom dress" after she reached out in his DMs, noting he was "on board from the beginning."

"I met with Michael months ago," Jarvis recounts. "We sat down, I just explained my vision, and he sketched up what I was describing, and it was exactly what was in my head. He's so talented."

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Jarvis and Costello picked out the fabric together, and she describes the finished product as "an elaborate, fully embellished beaded dress with rhinestones."

"It's more of a ... couture-style dress with a nod toward bridal," she adds. "So, it has different elements that give it a bridal last look, but it's very couture."

The Oppenheim Group real estate agent says Ducoulombier, 46, who created the mobile payment app Slip Cash, hadn't seen the dress ahead of the big day. "He hasn't seen the sketch of my dress, he hasn't seen the fabric, he doesn't have a clue," says Jarvis.

She accessorized the look with shoes by Rene Caovilla and custom jewelry, as well as some family heirloom pieces.

Jarvis and Ducoulombier dated for two years before getting engaged on Christmas in 2020. She tells PEOPLE that Lake Como is "a special place for us" while explaining why they opted not to have a "traditional wedding" with a bunch of guests.

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"We wanted to have a very intimate and romantic wedding day without all the traditional expectations around us," said Jarvis. "So we decided, let's the two of us go to Italy. We've been before and it's actually where I told him I loved him. He had already told me he loved me, but I held back for a little while."