Mmm... new idea occurs to me. The encounter begins on the porch/front yard... like if they were to have a picnic outside, something cute. At this point, the character notices only ambiguous signs. It could be a casual date with a friend. Then the observation of roses/champagne signal that it's more than that. As the story moves inside, the clothes identify who the perpetrator was, and by the time he reaches the top of the steps, there has been a steady progression building up exactly how momentous and startling this betrayal was.