Michelle and Barack Obama Credit: courtesy of the White House

On October 3, 1992, future United States President Barack Obama vowed to spend eternity with Michelle Obama -- and so far, he's made good on that promise.

"Twenty years ago today, I married the love of my life and my best friend," Barack, 51, tweeted October 3, 2012. "Happy anniversary, Michelle."

The First Lady, 48, replied via the social networking site, writing, "Happy 20th anniversary, Barack. Thank you for being an incredible partner, friend and father every day. I love you!"

Around 200 guests attended the couple's wedding ceremony at Chicago's Trinity United. "It was beautiful," Michelle's close pal, PR exec Yvonne Davila, once told Us Weekly of the couple, who met in 1989. "Her dress was beautiful. She was happy. She was marrying the man she loves."

More than two decades later, the spouses -- parents to daughters Malia, 14, and Sasha, 11 -- are solid as ever. "She's gorgeous. She's strong and smart and grounded," Barack once told Chicago magazine. "She's brutally honest, which is good for keeping my head on straight."

Because Barack is scheduled to participate in a live debate with Republican nominee Mitt Romney, 65, in Denver on his anniversary, the Hawaiian-born politician will celebrate the marital milestone October 6, a source tells Us.

"She's just happy that they got to be together for their anniversary," a source close to Michelle explains. "Even being together is not a forgone conclusion in the busy weeks leading up to the election."

To see how the couple's love has grown stronger with time, click here.