WATCH: Gay Marine who proposed to fiancé at White House speaks out against DOMA

In December, U.S. Marine Corps Captain Matthew Phelps made headlines when he took a knee at a White House holiday tour and proposed to his partner Ben Schock. The photo of their proposal (right) stood as a symbol for the increased national support for marriage between same-sex couples, the White House's personal embrace of the freedom to marry, and the amazing progress the U.S. military has made with gay and lesbian service members just one year after the repeal of 'Don't Ask, Don't Tell," the ban on openly gay servicemembers. 

Now, Phelps and his fiancé are speaking out about how they will be hurt by a different law - the so-called Defense of Marriage Act, which prohibits federal respect for legal marriages between same-sex couples - when they tie the knot in May, and how they're already being disrespected by the military and the federal government.  

Phelps and Schock are members of the American Military Partner Association, which has spoken out consistently about the importance of repealing DOMA so that all military families are protected. This week, the Center for American Progress released a powerful video featuring Phelps and Schock sharing their story and laying out the ways that DOMA explicitly damages their relationship and their lives.  

"A lot of people think that after 'Don't Ask, Don't Tell' was repealed, that was it - that everything was fixed," Phelps explains in the video. "But the reality of it is that the lives of the individual gay or lesbian service member was fixed. But repealing 'Don't Ask, Don't Tell' didn't change anything for our families."  

Soon, Phelps leaves for deployment in Japan, and in order for Ben to travel with his fiancé, he will have to live as a civilian, with no additional allowance to help the engaged couple live as a family. That's just one of the 1,100 protections and responsibilities that married same-sex couples are deprived of because of DOMA. 

In the video, Phelps credits the U.S. military for taking good care of the families involved in all branches of the military - and he explains that the military largely has its hands tied with regard to treating married same-sex couples the same as married different-sex couples. This month, the Department of Defense even announced that it would extend some protections to married same-sex couples - protections like military ID cards.

But until DOMA is repealed, gay and lesbian service members won't have access to those 1,100 other protections.

"People really take for granted how hard the government and the military work to support families and make sure that every time they're transferred to a new duty station the family doesn't fall apart," Phelps says. "Children are transferred in schools, spouses are transferred in jobs, and everything sort of happens automatically. But nothing happens automatically for us. The Marine Corps will continue to treat me as though I'm a single officer, not responsible for anything else - when the reality is that I'm responsible for my family the way any other Marine is."

"I have an obligation to the Marine Corps and to my country," Phelps says. "But I also have an obligation to Ben and to my family." He won't be able to fulfill those obligations until DOMA is repealed.

Check out the full video from the Center for American Progress below.

For more information about how DOMA hurts military families, check out Freedom to Serve, Freedom to Marry, our joint campaign with OutServe-SLDN that amplifies stories of military families hurt by DOMA.