Hmm, it does change quite visibly, but I think my first reading of it was that she was thinking about her own relationship with guys, which was pretty terrible (for understandable reasons).
It looks like she’s turning her thoughts inwards, you know? And especially since Marcela isn’t even talking about the depth of her feelings for Joshua, instead highlighting the physical aspect. While Vera seems to be thinking over how she doesn’t seem to enjoy the physical side at all.
But later on, when she asked about him in ep 7, “How’s it going with, what’s his name, Joshua?” I think then there might have been a little something. And then definitely in ep 10 at the hotel room when Carly tried to make her laugh about Joshua bringing Marcela to that room and instead just ended up making Vera really jealous. Also later on in the same ep when they were outside and Carly called him handsome and Vera was so irritated and immediately went no, mames.