Joe had a couple lines of dialog to confirm this. One was how he looked at her instead of through her with the "I just want to look at you" line Terry uses to prolong the experience, and the other was when he was in the bathroom talking to Dory on the other side and told her she was still very attractive which was one of the reasons why he was in the bathroom in the first place. And I think Owen and Terry might've cracked a couple jokes about it after Joe had told them.