UK man Matt Dechaine used the hashtag when sharing photos of himself and his husband and said his goal was "to spread joy".
"Seeing the hashtag was so uplifting," he told CNN.
"It feels like the movement for positive change for all is gathering momentum all the time and I'm glad to be a small part of it. By coming together rooted in respect and love for each other, the world can be so much better!"
Proud Boys leader Enrique Tarrio said he couldn't see what the men were trying to achieve.
"We aren't homophobic. We don't care who people sleep with ... One of the messages they want to send with this is that they're trying to drown out our supporters," he said.
"I don't think there's anything progressive about that. Why don't these people just engage?"
The Anti-Defamation League has called the group's ideology "misogynistic, Islamophobic, transphobic, and anti-immigration".
Several Twitter users took the opportunity to share photos from important moments in their relationships, calling themselves "the real #ProudBoys".
Patrick Strudwick wrote, "We grew up in a time when gay men had no rights, when newspapers called us poofs, when police didn't investigate when we were murdered.
"We're the real #ProudBoys."
