Ephram/Amy are a prime example of showing them "together" without the romantic tag always being in place throughout the series. During the time periods they weren't officially together romantically, you still felt like they were together because of that emotional connection. Even if season 2, Berlanti separated them a bit, he still had them together during very important moments while they were with Madison and Tommy. You still felt that E/A and their dynamic was 100% way more important than their temporary romantic relationships. They were together even when apart. I wish Mark would have done something like this with Leyton instead of giving them amnesia in season 2.