When was the first time Nathan and Haley đã đưa ý kiến always and forever?

I think, episode 3.16 when haley is trying to make sure that it's Nathan on the other side of the door.

I am pretty sure it's not 3.16, because if that was when they đã đưa ý kiến it for the first time, how would he know what to say? I think it was the wedding vows.