He posted a picture from the event with Liss and wrote a gushing message filled with the highest praise for his wife-to-be.
"HAPPY BIRTHDAY to my gorgeous fiancée!" he began.
He continued to list all the reasons he admires her but admitted he couldn't quite capture his true feelings in an Instagram post.
"An amazing partner.. an amazing mother & my soulmate. Love you more than any words on Instagram can describe," he finished.
In a separate post, Bryce uploaded some pictures from their "weekend shenanigans," which featured some MAFS alums from their season.
Jason Engler and Belinda Vickers posed with the happy couple as the sun set on Liss' party.
Belinda commented on the post with a '100' emoji, but it didn't take long for fans to respond to her comment about her treatment of the couple during their time on the show.
With one concerned fan writing: "You were horrible about Bryce & Liss when on MAFS. Glad you've seen the truth of their love."
Bryce quickly came to her defence, writing: "Belinda was actually really nice to us & stood up for us when others did what they did, but it was never shown on TV. That's why we're still friends to this day."
After he cleared the air, Bryce continued talking to his fans about how the show wouldn't use footage "where everyone was happy & all got along." But he also took a moment to slam Rebecca Zemek after a fan said, "she was not a nice girl at all."
"One of the most toxic humans we've ever met that one," agreed Bryce.
Finally, Jason shared his love for the couple by commenting, "Good friends are like stars in the sky….you don't always see them, but you know they're always there."
This article previously appeared on our sister site Now To Love.