"It was beautiful," Mann told PEOPLE about his May 22 proposal. "It was simple [with] lots of wine."
"It was just the two of us," Perloe said while attending the Los Angeles Film Festival premiere of Seeking a Friend for the End of the World, in which she has a small role.
"With The Voice, we'd been spending so much time with friends and family, and things were so chaotic, which was incredible, but it was really nice to just ... have the two of us just on our own," she said.
"We didn't need any more family!" Mann concurred.
The duo ditched their big plans for the evening, and Mann proposed during a quiet night in their hotel room.
"We literally had all these plans, and we ended up sitting in our hotel room by the fire and just having some champagne," said Perloe. "We didn't even want to go out to a fancy dinner or do anything. It was so nice."
Added the bride-to-be, "We've been together for so long, and we've just kind of been through thick and thin."