He shouldn't have let his dad ruin his relationship with Stacey. He knew about the "married man" - all but his identity and it was outside of Stacey and Bradley's relationship - he himself told Sean that she dumped the married man for him. He should have realised that she was not as much to blame as Max was and it would have been so much better if he walked with Stacey into Jack's flat and said something like "You thought me and Stacey would split up over this dad. Well you are wrong. I won't let your affair with her ruin my relationship with her" and then went somewhere else with Stacey out of respect for Tanya.