"1st pic out in public," the San Francisco winemaker posted under the pic.
A witness who saw the pair out and about tells Us Weekly, "Saw Ben and Courtney dining with two other guests in the North Beach neighborhood of San Francisco. She was wearing her ring and they looked cozy."
During Monday's Bachelor finale, Robertson beat out Lindzi Cox for the final rose.
"I want to tell you that you are my forever," Flajnik said during his heartfelt proposal. "I have waited a really long time to tell you that I am in love with you more than you will ever know and this whole experience and journey has been worth it every step of the way."
But things between the two aren't exactly a picture-perfect fairytale right now.
According to an insider, during the After the Final Rose episode, Robertson tearfully revealed that Flajnik abruptly dumped her three months after his proposal (which was shot in November), then reconciled with her just as Us Weekly caught him stepping out with three ladies.