During their garage conversation in Reunion 2.0, I just love how Aaron pretty much tells Robert that he can't fight how he feels anymore. He has tried to ignore it all, by trying to find someone else in Alex and failing, trying to prove to others that he was over Robert, but it has just made it all the more obvious that Robert is the only thing he ever wanted. Thus ultimately proving that they are inevitable and can't be apart from each other. He knows something is missing without Robert and needs him to feel complete and whole, which emphasises their co-dependency. In that moment, he is giving in to it all instead of tirelessly trying to fight it. He's so emotional in that scene because it has been painful for him to pretend that he doesn’t want and need Robert. Because I believe both are inherently part of him now, a basic need like breathing.
And Aaron’s reunion speech as he lists everything Robert has done for him - my favourite bit is when he talks about how Robert has loved him more than anyone else, in a different way to anyone else. Because he knows deep down that Robert’s love for him is unconditional and ferocious in its intensity, it can not be matched by anyone else. He knows everything Robert has done for him in the name of love. He acknowledges it and is grateful for it, and in that moment, it is a pivotal moment for Aaron, who doubted Robert’s love in the past. But he wants to be the one that is there to help Robert when he needs it, which allows them to put their love on a more healthy and even keel, thus setting up their reunion and relationship as healthier than it was in the past.