The model, 19, posted the black and white photo on Instagram, writing, “Happy Valentines babe .” In the photo, Richie is sitting close to Disick with their arms around each other, while both wear sunglasses.
Disick, however, did not reciprocate with a public Valentine’s Day wish of his own.
The couple has been dating for nine months, recently being spotted having a dinner date at Nobu in Malibu on Feb. 8.
Richie and Disick’s relationship seems to have progressed as the teenager has been seen spending time with her boyfriend’s three children whom he shares with Kardashian — sons Reign Aston, 3, and Mason Dash, 8, and daughter Penelope Scotland, 5½.
“Awww Scott and his kids,” Kendall Jenner — Kardashian’s sister — commented on a photo shared by a fan account of Disick riding in a car with his girlfriend and three children, adding a laughing face emoji.
RELATED VIDEO: Kendall Jenner Shades Scott Disick and Girlfriend Sofia Richie on Instagram
“You could tell that the kids don’t know Sofia well because they weren’t holding her hand. Instead, they all stayed close to Scott,” a source told PEOPLE of the situation. “It was a short dinner. Scott and Sofia were not affectionate. The kids seemed fine with her, but all sat close to Scott. He helped them at dinner and with potty breaks.”
The source added, “Sofia acted like Scott’s friend and you could tell she was trying a gentle approach to get his kids’ approval.”
Meanwhile, Kardashian opened up about her ex’s unhappiness with her relationship on a recent episode of Keeping Up with the Kardashians.
“Last night, Scott called me at like two in the morning — he never calls me late at night, ever,” she said. “And he was just ranting — like, ‘What are we doing in life? What are you doing? What am I doing?’ And I’ll go: ‘But what are you doing?’ But then he’ll say: ‘But what are you doing? Is it any better?’ By the end of the conversation, I just was like: ‘I have a boyfriend. He’s 24 years old. It’s not the craziest thing that’s ever happened in the world!’ And he was like: ‘He’s your boyfriend?!’ And then he hung up the phone.”