If you take your W out of the equation (which essentially - she has done already on her own by moving out and proposing D)
What will YOU gain by releasing the elephant, so to speak?
I mean, really and truly. Think about once it's done and said. Once the discussion happens (either an angry convo or not - it really doesn't matter).
What happens to BL's state of mind after? What happens to his ego? After you scratch that "ha-HA, I KNEW IT!!. See, you'll NEVER get one over me!" itch, will you feel better or worse?