The courtship of Phelps and Schock actually started back in 2010, when they met in Washington D.C., at the Servicemembers Legal Defense Network annual dinner. Phelps was living in San Diego at the time, while Schock was Seattle-based, so they exchanged contact information and stayed in touch.

Flash-forward to 2012. Schock was now living in D.C. and Phelps was in the nation's capital often for work.

Phelps, 35, graduated from Naperville North High School in 1995, then earned a bachelor's degree from the Eastman School of Music in Rochester, N.Y. After working at Walt Disney Entertainment, he enlisted with the U.S. Marine Corps in 2002, and is now a captain. In 2005, he became a logistics officer and spent 10 months in Iraq during Operation Iraqi Freedom. Phelps had come out as gay at age 18, in 1995, but went back in the closet when he joined the military.

Schock, 26, is now in school, pursuing a nursing degree after graduating with a journalism and Spanish degree from the University of Washington. He came out at 14.

This past May, through his involvement with OutServe, the professional organization of actively-serving LGBT military members, Phelps received an invitation to attend the LGBT Pride Month reception at the White House on June 15.

"When I got the invitation, I thought it would be a perfect time to ask him to go as my date," Phelps said. "I had to give him an offer he couldn't refuse because I really wanted to go out on a date with him, and that's the best thing I could come up with."

"It doesn't get much better than that [for a first date]," Schock said, laughing.

But Phelps actually had to do a bit of personal research before he officially invited Schock. Phelps casually sent Schock a text message, asking his thoughts about President Obama. Schock replied that he supports Obama, voted for him and hoped he was re-elected—and that he loved Michelle, too.

Phelps, with a smile, admitted that, if Schock replied that he hadn't supported Obama, "I don't think we'd be having this [interview]," Phelps said.

Phelps and Schock—wearing military attire and a suit, respectively—were among about 500 at the annual president-hosted Pride Reception at the White House.

And this was the first such event after the end of "Don't Ask, Don't Tell."

"I was nervous that night, for a lot of reasons," Phelps admitted.

But the reception went smoothly. Both enjoyed drinks and hors d'oeuvres, including, "the best grilled cheese sandwich I have ever had," Schock said with a smile. Phelps even got to shake Obama's hand—and the President thanked Phelps for his service.

After the reception, Schock had made reservations for dinner for the two.

"By the end of that night, I was completely sold," Phelps said.

The two even held hands along Pennsylvania Avenue en route to the restaurant.

So how do you follow that first date?

Well, their second date was just as amazing.

Later that month, Phelps flew home to San Diego to prepare for his change of command as he was the company commander at the recruitment depot. Schock, meanwhile, quit his job to further his education.

So Phelps invited Schock to San Diego to meet his family and participate—as his date—in this career milestone moment. Schock agreed.

The day Schock flew to San Diego, Phelps was participating in a sail boat race on San Diego Bay. Schock landed at the airport, took a cab to a restaurant and watched Phelps sail by. After the race, Phelps stopped at the dock to pick up Schock.

They had a champagne toast as they went back to the harbor to return the boat.

That was followed by a walk along the beach.

"That was the night I told Ben that I loved him and that we were going to be, us," Phelps said.

"I felt the same way," Schock said, "and was going to try my hardest to be with this man, to make him happy."

Both were pragmatic, though, knowing it had been a short time of them truly being together.

Their third date was just as jaw-dropping. Phelps took Schock to the Pentagon, where he spoke at the inaugural Department of Defense Pride Event.

Their parents met for the first time at the annual HRC National Dinner in October—and Phelps that night asked Schock's dad for permission to marry Schock.

In late November, they received an invitation for the Military Partners and Families Coalition, an LGBT organization, for a holiday tour at the White House. It happened on Dec. 15, no less—their six-month anniversary.

Phelps then went into thinking and planning mode, convinced Schock was Mr. Right for him.

Schock just wasn't in on Phelps' proposal plan.

In fact, when they went to the White House, Phelps had given the ring to a friend, so she could take it through security and Schock wouldn't see it.

"We got to the last stop on the tour, and near a Christmas tree, we walked up to it like we were going to take a picture, just like we had in front of other trees—and then I turned to Ben, dropped down on one knee, and asked him to marry me," Phelps.

The overwhelmed Schock instantly said, 'Yes.'

Plenty were snapping pictures—and photos of them went viral, as the two became the first same-sex wedding proposal at the White House. (In June 2012, Scout, a transgender man and also a former Chicagoan, proposed to his girlfriend Liz Margolies, and they were married in December.)

"That was the happiest moment of my life," Schock said, "and I will admit I was completely shocked, completely blown away, totally surprised."

That wasn't it for Phelps' wild night—and Schock's surprise. They went to a nearby hotel for an engagement celebration with about 30 of their friends. Schock didn't know any were going to be there.

"We never anticipated the evening to have an impact beyond the following morning," Phelps said.

However, the two have been media darlings, and they even were included in commentary from talk-show host Conan O'Brien.

"It's a really weird feeling to think that what we're doing is making history because we're just living our lives. This is just Ben and Matthew," Phelps said. "That said, if people recognize this as something special and there's something to be drawn from this, then fantastic.

"If us being the public face of equality, and that moves equality along, we're all for it."

Phelps and Schock are planning a May marriage—in Washington D.C., or Washington state.

"We have some challenges ahead because the Defensive Marriage Act is still intact, so, when I get [deployment] orders to Japan this [upcoming] summer, which I'm expecting, the government is not going to recognize our marriage, so Ben is not a dependent and will not be going over there officially with me.

"It's a dark cloud over us."

But both remain optimistic.

"I still really love the Marine Corps and we're going to get this all settled," Phelps. "My [Marine] colleagues have been among the first to congratulate us."

In fact, the first congratulatory phone call Phelps received after the proposal was from a straight Infantry officer.