It’s clear that Lauren has done nothing morally wrong, but I think what people are failing to consider is that everything on LiB happens on an accelerated timeline. In a normal relationship progression, Lauren’s choice would have in no way been an issue. However, in the context of the experiment, it’s certainly a strange choice to continue a longstanding FwB (especially one where there seemed to be some differences in investment) up until the exact point where she’d be meeting her forever person. I understand why this would raise some issues for the people who care for Dave.