I would confront. Then tell your W you know she has been contacting him. She will argue saying that she hasn't, etc. Before she goes too far into her tirade.
Hold your hand up and just say, "I know you did and that's that". Then walk away. Don't give her a chance to "explain".
M-43 W-40 2D - 9 and 5
Emotion, yet peace. Ignorance, yet knowledge. Passion, yet serenity. Chaos, yet harmony. Death, yet a new life.