"Before I got engaged, I said that I don't want to get married until marriage is equal for all," Mraz, 33, told PEOPLE at last week's Elton John benefit concert for the American Foundation for Equal Rights in Beverly Hills. "So now I'm engaged, and we want to get married some day. So this kind of really puts us in the fight."
Mraz, who popped the question in December, is hopeful and even confident that he'll be able to say "I do" before too long.
"It will probably go to the Supreme Court," Mraz says of current legislation banning gay couples from marrying. "And in two to three years, hopefully the Supreme Court says it's unconstitutional, gives it up, and then marriage will explode throughout the country. Mine will be one of those."
For now, the singer-songwriter is basking in the glow of being newly engaged.
"It's great," Mraz gushed while making eyes across the room at his fiancée, who served as the inspiration for his most recent hit, "I'm Yours." "Just in general in my world, I see life through a completely different filter."
He adds, "There's actually more freedom. Now I really get something to be romantic about. It isn't just about looking romantic or wondering where my next opportunity to be romantic will be. Now I know where it's at."
While Mraz and Prettyman are content to put their wedding date on hold, they still have plenty to celebrate. Concludes the one-day groom-to-be, "Definitely [there's]a lot of love in my life these days."