Rather than throwing her under the bus, you need to establish personal boundaries. Tell her that as long as she is seeing the OM, she cannot stay with you and your son. She has to hit rock bottom on her own.
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.