Should I just leave now or wait for him to start fucking my wife

When my wife heard my old college bud was coming over, she ran upstairs, I figured to make herself presentable for his arrival. But when the doorbell ran, she came downstairs and answered it in the sheer bikini I bought her for our anniversary, the one she swore she would never wear!

Now as he smiles at my wife, a very visible bulge forms in his pants, and my wife acts all shy around him, I wonder if I should just leave now or wait for her start fucking him...

She came downstairs in the bikini