The fact that he said that though makes me happy. I’ve seen a few people say that he still needs to tell her, and I agree, and this lets us know that we can assume he has. So going into 4b, I’m thinking that maybe Emma is caught up and they are starting as a “couple” with no…

Yep, same here. I'm pretty sure she'll know by the time we catch up to them again, just like I'm actually pretty sure she knows about Ariel and a few other things. I'm also sure that we won't see him tell her, unless it's necessary for plot purposes to introduce some new conflict or arc. There'd be no point, it would be repeating information and dialogue that the audience has already seen. There've been plenty of times, so far, where someone has referenced something that they were never specifically told on-screen. Some conversations can happen off-screen, if they don't contain any new information for the audience; this is definitely one of them.