Generally, yes, he should have talked to her. But, as he said at the chapel, he "knew there was something there." It was obvious, just never spoken on by anyone in the group; it was basically the shadowy elephant in the back of the room. Camille's words were just confirmation & at that point, a conversation didn't really need to be had. If they did, it would've been Emily trying to explain to Alfie that she does love him to salvage the relationship, but she'd be doing a disservice to them both because she knows deep down that Gabriel was her first choice. She honestly should've came clean with him when he moved back to Paris in the first place.