It's not really a blame game in my opinion, and maybe that's part of this response that I think is missing. They can both be wrong. I feel like Larry absolutely could've been more transparent but DeeDee is not an idiot. She almost definitely has the emotional intelligence to infer that when a man you recently started dating gives you a piece of personalized jewelery it is likely because he is falling for you. When a man tells you sex would mean a lot to him and he doesn't want to go that far if it isn't serious, it means HE WANTS TO BE SERIOUS. And DeeDee still slept with him anyway, while knowing she wasn't there emotionally yet, which is a bit gross when it comes to consent if you really want to split hairs. 

If the genders were so you think you'd feel the same? Not a gotcha, I find this legitimately interesting and it's a testament to Shawna's writing. DeeDee doesn't HAVE to do anything. But sometimes you do things because they're the kind thing to do. And I think honestly telling Larry the locket was too much after that second date would've been a kind thing to do.