Hi, A while back I read a story where Brian and Justin had either dated or hooked up before the series and without the rest of the family knowing. They then met again at either Deb's or Mel & Lindsey's place for dinner with the family. This might not be the first meeting after their break-up that they met again. After something happened Justin defended Brian, letting everyone know they had dated before. I also think Gus knew about their relationship before the dinner.