That was one of my problems with the ending. The writers went way OTT because they were mocking the fans desire to see Brian and Justin end up together. And Judtin saying in the end that Brian wasn't himself was just another way to make Justin seem like he didn't know what he wanted(something the writers did from the time Justin and Brian reunited in S3)and keep Brian the single club boy he was in the beginning. The fact is they could've shown the two of them committing without all the OTT stuff and it would've been a much more satisfying ending.
I like justinlovesart's stories because she does show them in character,with both characters growing and Justin not EVER being the "damsel in distress" that he often is in other stories(,or a doormat or someone who worships Brian and comes to think everything Brian says is right). You can find her stories on bjfic. I'm not sure where else they're located.