The 34-year-old model and her tech entrepreneur beau, 39, took their family and friends by surprise when they tied the knot on Saturday in Mexico.
The happy couple had been holidaying with their nearest and dearest, and chose to say "I do" on the beach as the sun was setting in the background.
"My happiness is indescribable!" Stacy told PEOPLE. "Marriage is the ultimate bond of love and friendship. It means putting all your faith and trust into a person that you can't help but believe is your soul mate.
"Someone who has all of your best interests at heart; someone handpicked for you, to help you grow and be the best person that you can be. Jared is all of this for me."
The couple, who are said to have been dating since August, had been planning the low-key nuptials for several months — unbeknown to most of their family and friends. This is the first trip down the aisle for both.
"We both felt strongly that our 'love day' should be intimately special, and that's exactly what it was," the newlyweds told the publication in a statement. "It was a blend of romance, tranquillity, natural beauty, bonding and overwhelming love."
Stacy and Jared, who is the CEO of private interactive firm Future Ads, have been friends for over five years. The lovebirds started dating shortly after Stacy split from George Clooney. At the time, the Maryland-born beauty assured fans that the break-up had been amicable.
"There's nothing really dramatic that happened," she said. "It's all good. I'm someone that's always lived the present moment. I always look at the positive in everything."
The actress model was apparently the one who called time on their two-year relationship, as she wanted to have children and a family someday. "She knows where George stands on that," an insider told the publication at the time.
The Hollywood actor is currently linked to British barrister Amal Alamuddin. The two were spotted cosying up at a special screening of George's new film, The Monuments Men, at the White House last month.